Python Practice Problems

Python (394)

• Activity Time Ledger - easy - Matching activities. One runtime.
• Birds of a Feather - medium - Every record finds its kin; keep them in the order they arrived.
• Batch Records - medium - Too many at once. Break them into groups.
• Batch With Metadata - easy - The list gets chopped.
• Caesar Shift Check - easy - The key turns. Does it open?
• Letters in the Noise - easy - Case and punctuation are distractions. Find what each letter really weighs.
• Char Profile - medium - Every character in the string tells a story.
• The Fallback Layer - easy - When the live values come back empty, something has to stand in.
• Column Max - easy - One value rules the column.
• Column Range - easy - From minimum to maximum. What is the spread?
• All Told - easy - Every shift leaves a number behind. Total the fleet.
• Common Prefix - hard - They all start the same way. How far?
• Cumulative Sum - medium - The total grows with every row.
• Data Quality Report - hard - The data is not as clean as it looks.
• Deep Flatten - medium - Nested deep. Flatten everything.
• The Path Inward - medium - Every setting hides a few levels down. Follow the route, or come back empty.
• Detect Cycle in Sequence - medium - Follow the chain long enough and it might loop back.
• Detect Outliers - medium - Most values are normal. Some are suspicious.
• Diagonal Extract - medium - Not every value sits in a row or column.
• Dice Roll Scoring - medium - The pattern rewards the patient.
• Dictionary Key Intersection - medium - Two dictionaries. What do they share?
• Distribute Values Into Container Types - medium - Round-robin the values. Keep rotating.
• Dominant Element - easy - Majority element. Appears more than half the time.
• Even Filter - easy - Only the even ones survive.
• Execution Timer Wrapper - medium - Function wrapped with a timer. Duration captured on exit.
• Explode List - easy - One row holds many values. Unpack it.
• Extract Domain - easy - The domain is buried in the string.
• Extract Leaf Values - medium - The tree has leaves. Pluck them.
• Find Indices - medium - It is in there somewhere. Where exactly?
• Find Mode - medium - One value appears more than the rest.
• Who Came First - easy - The feed repeats itself. Keep each member only the first time it speaks.
• Flatten the Feed - easy - Nested lists, all the way down.
• Flatten the Nest - easy - Mixed nesting. One flat list out.
• Full Outer Zip - medium - Two sides. No value left behind.
• Greeting Formatter Class - easy - First impressions are formatted carefully.
• Group Average - hard - Same group, different values. What is typical?
• Group By - medium - Same key, different rows. Bring them together.
• Lag Column - medium - What came before this row?
• Left Join - medium - Keep the left side. Match what you can.
• Majority Event in Stream - medium - One event type is drowning out the rest. Find it without a frequency table.
• Max Length Token - medium - The longest token wins.
• Merge Counters - medium - Two tallies. Combine them.
• The Overlap - hard - Overlapping windows are one outage. Collapse them into the truth.
• Merge Overlapping Time Ranges - medium - Intervals piling up. Clean the timeline.
• Flat Memory - medium - Two sorted runs, one buffer, no scratch space. Fold them together where they already live.
• Normalize Name - easy - Names are messy. Standardize them.
• No Shortcuts - easy - The peak value. Built-ins off the table.
• Null Counter - easy - How many holes in the data?
• The Most Specific Rule Wins - medium - Every packet asks the same question of the firewall. Answer it the way the table intends.
• Ordered Character Check - easy - Check if all As appear before all Bs.
• Palindrome Hunt - medium - It reads the same both ways. Go further.
• Parse Log Line - medium - One line. A dozen fields hidden inside.
• Permissions Manager - medium - Manage user permissions with config updates.
• Pivot Records - hard - Long format is easy. Wide format is useful.
• Portfolio Profit Calculator - medium - Portfolio gain from purchase history and current prices.
• Precision and Recall - medium - Precision and recall. Both matter.
• Prefix Based Word Replacement - medium - Every word trimmed to its root.
• Progress Milestones - easy - Progress at every 10% increment. Keep the receipts.
• Quality Gate - easy - Not everything passes inspection.
• Quantile Calculator - easy - Mark the boundary value at a given point.
• Points of Order - medium - Every page makes its case for the top. Settle it, and settle the ties.
• Every Line on the Receipt - medium - Nested deep inside the receipt. Pull every item out.
• Record Filter - easy - Some records belong. Others do not.
• Rename Keys - medium - Old names out. New names in.
• Reverse Field - easy - Flip it. See what happens.
• Full Circle - medium - Load has to keep moving. Pass it down the line.
• Row Aggregates - medium - Each row holds its own summary.
• Run Length Encoding - easy - AAABBB becomes 3A3B. Compress it.
• Running Distinct Count - medium - New values keep appearing. Track the count.
• Sanitize Field - easy - Dirty input. Clean output.
• Schema Checker - easy - The schema says one thing. The data says another.
• Sequential Word Pairs - easy - Everything has a neighbor.
• Shortest Unique Metric Tag - medium - One token per metric. Make it unambiguous.
• Single Element Among Pairs - easy - One element has no partner.
• Sort Descending - easy - Biggest first. No exceptions.
• Stock Range Finder - medium - Prices move. One stretch had the widest gap.
• Stream-Process a Large CSV - hard - Too big to load. Read what you can.
• Subarray Signal - medium - One stretch carries the strongest signal.
• The Account Manager - easy - Deposits, withdrawals, and the risk of going negative.
• The Additive Chain - easy - Each value is the sum of the two before it - no calls to itself allowed.
• The Address Surgeon - easy - One string hides a street, a city, a state, and a zip.
• The Alphabet Score - easy - Every letter has a secret numeric value - what's your total?
• The Alphabet Sorter - easy - Filing cabinet logic: everything goes in its proper drawer.
• The Anomaly Detector - hard - Spot the outliers before they page someone.
• The Balanced Inspector - medium - Every branch should carry the same weight.
• The Balanced Sum - easy - Some numbers have a rare quality that mathematicians revere.
• The Bipartite Test - medium - Can this crowd be split into two perfectly separated groups?
• The Bit Counter - easy - How many lights are on in the binary representation?
• The Bit Ladder - easy - Count the ones all the way up.
• The Bit Reverser - medium - Sometimes the answer is literally backwards.
• The Bitwise Judge - easy - No division, no modulo - just a single bit tells you everything.
• The Blind Multiplier - medium - Compute the result of everything around you - without seeing yourself.
• The Bonus Round - medium - Consecutive matching dice rolls trigger a special scoring rule.
• The Bouncer - easy - Every door has a guest list.
• The Bracket Validator - easy - Brackets opened and closed. The nesting might be off.
• The Bronze Medalist - easy - Not first, not last - somewhere in the middle of the podium.
• The Budget Allocator - medium - Split the money. Some wore two hats.
• The Bug Spotter - easy - It compiles. The answer is still wrong.
• The Build Order - medium - Some tasks must wait for others to finish first.
• The Calendar Sort - easy - Time has its own opinion about order.
• The Carousel - easy - Keep moving, same ride.
• The Category Ranker - medium - Categories have standing. Rows get theirs.
• The Chain Builder - medium - Links connect in sequence - build the chain from scratch.
• The Chain Transform - medium - One small step at a time can cover a great distance.
• The Change Data Capture - hard - Inserts, updates, deletes : all present.
• The Change Tracker - medium - Before and after snapshots. The delta is in there.
• The Character Clans - medium - Words sharing the same letters belong to the same clan.
• The Character Encoder - easy - Squeeze a string down to its tightest form.
• The Character Map - easy - Character-level frequency. As a dictionary.
• The Chunked Reader - medium - Too big for memory. Read in pieces.
• The Cipher Wheel - easy - Every letter has an alias - you just need the right codebook.
• The Clock Angle - easy - Two hands. One gap. One number.
• The Clock Examiner - medium - Two hands on a clock - how wide is the gap?
• The Code Expander - easy - Compressed messages need a decoder to come alive.
• The Coin Vault - medium - Exact change only - and you want to use as few coins as possible.
• The Column Shuffle - medium - Rows in, columns out. Number them.
• The Column Transformer - easy - Each column gets its function.
• The Roll Call - easy - Every value is waiting for its name.
• The Complement Hunt - easy - Every number is looking for its other half.
• The Config Blender - easy - Config collision. The surviving values after a merge.
• The Consecutive Sequence Finder - medium - Numbers that flow without interruption.
• The Consecutive Streak - medium - Login streaks. No gaps allowed.
• The Counting Machine - medium - It knows where it stopped last time.
• The Crowd Favorite Eatery - easy - One restaurant clearly won the most hearts.
• The Crowd Pleaser - easy - One value shows up more than all others combined.
• The Crowd Splitter - easy - The middle holds even with a dominant outlier.
• The Custom Iterator - medium - Some sequences follow their own rules.
• The Cycle Detector - medium - Follow the chain long enough and you might end up where you started.
• The DAG Executor - hard - Wire up a mini pipeline and watch it run.
• The Date Sorter - medium - Jumbled calendar. Sort it first.
• The Decomposer - easy - Every composite thing can be broken down to its simplest parts.
• The Deep Config - medium - Nested config, dot-notation output.
• The Deep Dictionary - easy - One key goes further than the rest.
• The Deep Dive - easy - A specific position in the unsorted pile.
• The Deep Selector - easy - Tell it what you want. It knows where to look.
• The Deep Unpacker - easy - Boxes inside boxes. Eventually you reach the bottom.
• The Dependency Resolver - medium - Everything depends on everything.
• The Depth of Field - easy - Some containers hold containers that hold containers.
• The Diagonal Accountant - easy - Two diagonals cross in the center of every square.
• The Dict Comparator - medium - Two dictionaries. Subtle differences.
• The Mirror Index - easy - Every value remembers who pointed to it.
• The Dominant Signal - easy - Hottest items in the transaction log. Ties included.
• The Double-Ended Gateway - medium - Some queues let you skip the line from both ends.
• The Duplicate Spotter - easy - Some values appear more than once - report only those.
• The Dynamic Container - hard - Build your own resizable list with no help from the standard library.
• The Elevator Trace - medium - Nested floors. One path through.
• The Email Ranker - medium - Some inboxes see more action.
• The Encoded Signal - medium - The encoding is hiding multipliers. Decode it.
• The Even Checkpoint - easy - Is this number in the even club? Prove it the fast way.
• The Event Aggregator - medium - Bucket a firehose of events into tidy time windows.
• The Event Broadcaster - medium - Subscribers show up, listen, and sometimes leave.
• The Event Bucketer - easy - Logs slotted into buckets.
• The Event Overlap Detector - medium - Overlapping events. The calendar knows.
• The Event Window - medium - A five-minute window is all that matters.
• The Eviction Policy - medium - Fixed capacity. Oldest unused entry gets evicted.
• The Exception Handler - medium - Good code handles failure as gracefully as success.
• The Expander - easy - What goes in small comes out big.
• The Face That Breaks the Bank - medium - Roll enough dice and one number always runs away with it.
• The Family Reunion - medium - Two cousins share a common ancestor somewhere above.
• The Fast Climber - medium - Some routes up the mountain are faster than others.
• The Field Counter - easy - Some fields speak louder than others.
• The File Size Profiler - medium - File types and their disk footprint. One type dominates.
• The File Tree Builder - medium - Flat paths. Build the nested tree.
• The First Class Function - medium - Functions travel as values - prove you can pass one around.
• The First Encounter - easy - Every character has a story - but only if you remember where it started.
• The First Stranger - easy - In a crowd, the unique ones stand out first.
• The Flat Mapper - medium - Nested values. One flat stream out.
• The Forbidden Ceiling - easy - Round up. But not the obvious way.
• The Forbidden Sorter - medium - Put the letters in order without the obvious tool.
• The Forgetful Machine - medium - It remembers everything, until it does not.
• The Forward Fill - easy - Patch the gaps in a noisy sensor stream.
• The Frequency Eviction - hard - When storage is tight, something has to go.
• The Gap Filler - easy - Fill the Nones with the last real value.
• The Gap Reporter - medium - The missing IDs in the log - somebody has to notice.
• The Gate Keeper - easy - Not all openings have a closing.
• The Generous Ones - medium - The generous ones are obvious.
• The Genre Filter - medium - Three tables, two conditions, one actor's total.
• The Grid Pivot - easy - A different angle reveals a completely different picture.
• The Half-Life Search - medium - Every guess cuts the problem in half.
• The Halftime Score - easy - Middle value of a dataset. No built-in shortcuts.
• The Hash Stamper - easy - One input, one irreversible output - the foundation of every secret.
• The Hierarchy Builder - hard - Parent-child pairs, flat. Build the family tree.
• The High Mark - easy - Scan the list. Report the max.
• The High Rollers - medium - Not every gambler bets the same - some wager far more than others.
• The Horizon Scanner - medium - For each position, what is coming up ahead?
• The Hostile Takeover - medium - One dict eats another.
• The Host Ranker - medium - Some hosts have more to offer.
• The Hourly Bucket - medium - Timestamps belong somewhere.
• The Impersonator - medium - You only have stacks. Make a queue anyway.
• The Indivisibles - easy - Numbers that yield only to themselves.
• The Infection Spread - hard - It starts with one, and then it spreads.
• The Integer Sieve - easy - Not everything in this list belongs here.
• The Intervals - medium - Timestamps in buckets.
• The Inverted Triangle - medium - A pattern of stars narrows toward the bottom.
• The IP Validator - easy - Real and fake, mixed together.
• The Island Counter - medium - Surrounded by water, connected by land - how many separate landmasses?
• The Last Instance - easy - When duplicates appear, only the last one counts.
• The Last Seen Map - easy - For each character, where did it appear last?
• The Lazy Squares - easy - A sequence that never fully reveals itself.
• The Lazy Stream - hard - Yield values one at a time from a potentially infinite source.
• The Lazy Unpacker - medium - Instead of loading it all at once, yield it one piece at a time.
• The Letter Census - easy - Every crowd has its share of talkers and quiet ones.
• The Letter Frequency Map - easy - Count every character in the string and report the results.
• The Letter Kin - medium - Words that share the same letters belong together.
• The Letter Ledger - easy - Every character has a count to answer for.
• The Letter Mapper - medium - A consistent substitution, or not.
• The Letter Tally - easy - Each character in the string has a count to answer for.
• The Level Inspector - medium - Each floor of the tower tells a different story.
• The Level Summer - medium - Add up each level of the tree.
• The Line Cutter - easy - Did everyone with an A-pass get through before the B-crowd arrived?
• The Line Splitter - easy - Comma-separated truths, one at a time.
• The Link Shrinker - medium - Long addresses have aliases - you give them out, you keep the map.
• The List Merger - easy - No shortcuts.
• The Load Balancer - medium - Distribute incoming requests evenly across available servers.
• The Log Decoder - easy - Every line holds a secret.
• The Log Pulse - easy - Some lines repeat themselves.
• The Lone Character - easy - It appeared exactly one time. That made it special.
• The Lone Traveler - easy - One character stands apart from the crowd.
• The Manual Sorter - easy - No shortcuts, no built-ins, just work.
• The Map Reducer - medium - Map it. Reduce it. One answer.
• The Market Streak - medium - Some stocks run longer than you think.
• The Market Timer - medium - One buy, one sell - when do you make the most?
• The Matching Manifest - easy - Two warehouses, one shipment - only load what's in both.
• The Median Keeper - hard - The middle value keeps moving as new data arrives.
• The Meeting Room Allocator - hard - Meetings overlap on the calendar. Rooms are limited.
• The Merge - easy - Chaos in. Order out.
• The Merge Champion - medium - Many sorted rivers flowing into one.
• The Messy Pipeline - easy - The upstream API has no idea what a schema is.
• The Middle Ground - hard - The middle value keeps moving.
• The Min Tracker - medium - The stack remembers the best it ever saw.
• The Minutes Tracker - easy - Some activities eat more time than others.
• The Mirror Flip - easy - Sometimes the fastest fix is to swap everything.
• The Mirror Image - easy - Flip the tape backwards - start from the end.
• The Mirror Test - easy - Check if a string reads the same forwards and backwards.
• The Mirror Words - easy - Each word looks back at itself.
• The Missing Number - easy - Something is missing from the sequence.
• The Molecule Report - easy - Four letters. A lot of math hidden in the sequence.
• The Month-by-Month Snapshot - medium - Every salesperson has a story. The months just tell it sideways.
• The Mountain Peak - medium - The sequence has a summit.
• The Multiplication Trail - easy - Each step multiplies the whole journey.
• The Multiplier Rush - medium - Negatives cancel negatives - but only if you keep both in view.
• The Narrow Lens - medium - A narrow timeframe. Everything inside matters.
• The Nearest Value Mapper - medium - Close enough counts. Ties go low.
• The Never-Ending Sequence - easy - Sequence that keeps going. Follow it.
• The Numbered Chair - easy - A standing list. Position n holds one entry.
• The Number Miner - medium - JSON strings are hiding numeric secrets - dig them out.
• The Number Narrator - medium - Every number has a story in words.
• The Number Screen - easy - Some numbers make the cut. Most do not.
• The Odd Digits - easy - Hidden inside a mess of characters are a few odd numbers.
• The Odd Extractor - easy - Not all numbers from a string are welcome here.
• The Odd Filter - easy - Strip out everything that does not belong to the odd club.
• The One-of-Each - easy - Strip the repeats, keep the originals.
• The One-Timers - easy - Values that never repeated.
• The One-Way Street - easy - Monotonic time-series. Direction only.
• The Onion Layer - hard - Peel from the outside in - one ring at a time.
• The Online Elite - medium - The top performers are hiding in the data.
• The OOP Pillars Exam - medium - Four principles, one class hierarchy - show you know all of them.
• The Op Dispatcher - easy - Name the operation, apply it everywhere.
• The Order Enforcer - easy - Some rules say every A must come before every B.
• The Order Inspector - medium - A binary tree has rules - is this one actually following them?
• The Original Keeper - easy - Clean up duplicate events without losing the timeline.
• The Output Peak - hard - One stretch outpaced all the others.
• The Overlap Finder - easy - Two guest lists - who made it onto both?
• The Page Turner - medium - Nobody loads everything at once.
• The Pair Counter - easy - How many pairs can be formed from the crowd?
• The Paired Doors - easy - Every open bracket has a partner - but not every partner shows up.
• The Pandas Pivot - medium - Rows become columns. Columns become power.
• The Parentheses Factory - medium - Building balanced brackets is an art form.
• The Pascal Row - easy - Each number is the sum of two numbers above it.
• The Password Builder - easy - Random characters, fixed rules.
• The Password Forge - easy - Does this password pass the strength gate?
• The Pay Ladder - medium - Climb the ladder the hard way. No shortcuts allowed.
• The Payload Flattener - medium - Turn a deeply nested API response into a flat row.
• The Peak Finder - easy - Largest number in the list. Max() is not an option.
• The Perfect Match - medium - Two numbers walk into an interview...
• The Pipeline Filter - easy - In the door as one thing, out the door as another.
• The Placement Fixer - medium - Each value belongs in exactly one spot.
• The Postfix Processor - medium - Math without parentheses - the operators come after the numbers.
• The Precision Hunt - medium - Some answers need no decimal point.
• The Price Bander - easy - Different prices, different treatment.
• The Priority Queue - medium - When two things tie, something has to break the deadlock.
• The Progress Meter - medium - Report progress at every tenth of the way through.
• The Progress Parade - easy - Just tell them how far along you are.
• The Quarter Turn - medium - One rotation changes everything.
• The Queue Disguise - medium - A queue in sheep's clothing.
• The Ranked Dict - easy - Values deserve order too.
• The Record Reconciler - medium - Two versions of the same truth.
• The Repeat Offenders - easy - Repetition is a clue.
• The Repeat Review - medium - The echo came back.
• The Repeat Visitor - medium - Loyal customers come back sooner than expected.
• The Response Aggregator - medium - Multiple result pages. One clean summary.
• The Resume Sifter - medium - Pull what's useful. Skip what you know.
• The Rolling Peak - medium - The sweetest stretch in the sequence.
• The Rolling Window - medium - Smooth things out, one step at a time.
• The Roman Converter - easy - Roman numerals decoded.
• The Rotated Array - medium - Someone shuffled it. Now locate what you came for.
• The Runner-Up - easy - Not the winner. The one just behind it.
• The Running Total - easy - Each position holds the sum of everything before it.
• The Safe Caster - easy - Type conversion is easy, until it is not.
• The Schedule Cleaner - medium - Overlapping sessions. One clean line.
• The Schema Diff - medium - Two versions of the same config - what changed between them?
• The Schema Differ - medium - Schema from yesterday vs today. Something changed.
• The Schema Migrator - hard - Old schema in, new schema out.
• The Scoreboard Race - medium - Simulate rounds until someone hits the target.
• The Score Sorter - easy - Points on the board, sorted by who earned the most.
• The Scramble Check - easy - Same letters, different order - are these two strings secret twins?
• The Second Summit - easy - Not the top of the mountain - just below it.
• The Secret Twins - easy - Same letters, different disguises.
• The Self-Portrait Number - easy - Some numbers describe themselves perfectly.
• The Sequel Spotter - easy - Spot the sequels hiding in the catalog.
• The Shadow Cleaner - easy - Remove the repeats. No shortcuts.
• The Shifting Standard - medium - A benchmark in motion.
• The Short Address - medium - Turn a big number into a compact alphanumeric code.
• The Shortest Route - medium - Fewer hops is always better.
• The Silent Locator - easy - Every lookup should cost you less than the one before it.
• The Silver Screen Summit - medium - Box office totals decide who makes the top of the marquee.
• The Single Bit - easy - One particular pattern hides in plain sight.
• The Slow Leak - medium - Nested iterators. One flat stream.
• The Sneaky Twins - medium - They look different but they are the same inside.
• The Social Graph - easy - Everyone knows someone.
• The Solo Act - easy - One-and-done values only.
• The Spin Doctor - medium - Ninety degrees, but which way?
• The Spiral Harvest - medium - The snail reads the grid in its own special order.
• The Spread - easy - Data spread around a center. The range matters.
• The Squeeze - easy - aaabbb gets old fast. Shrink it.
• The Staircase Problem - medium - One step or two, the choices add up.
• The Status Board - medium - Make sense of a pile of raw Nginx access logs.
• The Step Counter - easy - You can hop one step or two - how many ways to reach the top?
• The Streak Breaker - easy - It has a problem with repetition.
• The Stream Averager - easy - The answer moves with the data.
• The Stream Joiner - hard - Events don't wait for each other. This does.
• The String Shrinker - easy - Compress the string. Shorter wins.
• The Style Guide - easy - Not every word deserves the same treatment.
• The Subarray Tally - medium - How many hidden windows hit the target?
• The Syntax Sentinel - easy - Brackets opened and closed. The nesting might be off.
• The Table Thief - medium - Somewhere in that query, tables are hiding.
• The Tag Analyst - medium - Two sets of labels, one analysis.
• The Tail End - easy - Push, pop, peek. The basics that break people.
• The Tail Finder - medium - Navigate to the end of a linked list using recursion.
• The Tail Trimmer - easy - Remove the k-th item from the back without counting forward first.
• The Tally Counter - easy - How many times does a single guest show up to the party?
• The Target Hunt - medium - Pairs that hit a target. Every one of them.
• The Throttle Ceiling - medium - Too many requests in too short a timeframe. Throttle it.
• The Throttle Wall - hard - Stop the abusers. Let the rest through.
• The Timezone Trap - medium - Trip data and timezones. They're not the same thing.
• The Timing Decorator - medium - Wrap any function to capture how long it takes.
• The Title Ladder - medium - Job titles and the salary tier they belong to.
• The Top Reviewer - easy - One restaurant receives the most feedback - which one?
• The Top Words - medium - In every document, some words dominate the conversation.
• The Trade Log Aggregator - medium - Every trade left a footprint.
• The Trade Signal - easy - Buy low, sell high. Identify the ideal moment.
• The Traffic Director - easy - Spread the load evenly - nobody should be doing all the work.
• The Trapped Pool - hard - What collects in the valleys after the rain?
• The Tree Measurer - easy - How deep does the rabbit hole go?
• The Trip Aggregator - medium - Travel records hold patterns waiting to be surfaced.
• The Trip Grouper - easy - Where did everyone go, and for how long?
• The Triple Alliance - hard - Three numbers, one target.
• The Triplet Hunt - medium - Every path that works gets a seat at the table.
• The Type Sorter - easy - A mixed list is hiding its numbers - extract them.
• The Value Sorter - easy - The order was always negotiable.
• The Velvet Rope - medium - Some users get in. Others wait outside until the window resets.
• The Version Parade - easy - 1.0 before 2.0. Don't let the dots confuse you.
• The Version Ranker - medium - Software versions follow their own ordering rules.
• The Vocabulary Test - medium - Can you spell out the whole sentence using only the words you know?
• The Vowel Hunt - easy - Just the vowels. All of them.
• The Waiting Game - medium - Patience has a price - and a count.
• The Water Collector - hard - Two walls, one sky, and a very important question.
• The Water Gauge - medium - Elevation bars trap water between peaks - count the volume.
• The Window Cleaner - medium - Keep it fresh, keep it unique.
• The Word Census - easy - Who said what - and how many times?
• The Word Counter - easy - How many times does each word show up in a file?
• The Word Families - medium - Different spellings, same letters - they belong together.
• The Word Flipper - easy - The sentence stays, the words surrender.
• The Word Inventory - easy - Every word, twice over.
• The Word Map - easy - Input text. Output: word frequency.
• The Word Mismatch - easy - Some text does not match.
• The Yahtzee Engine - hard - Five dice. Six faces. Score it.
• The Yahtzee Scorer - medium - Dice scoring. Multiple categories evaluated.
• The Zero Propagator - medium - One zero can change the whole picture.
• The Zigzag Encoder - medium - The message snakes its way across the rails.
• Threshold Filter - medium - Above the line or below it.
• The Spaces Between - easy - Raw lines arrive padded and uneven. Recover the fields that matter.
• Top N Keys - medium - Most of them do not matter. The few that do stand out.
• Transform Column - easy - Same data, new shape.
• Transpose Table - medium - Rows become columns. Columns become rows.
• Triangle Validator - medium - Not every triangle is a triangle.
• Type Caster - easy - Wrong type. Fix it.
• Unbroken - easy - A single dip resets the clock. Find the longest the machine held over the line.
• Unflatten Keys - medium - Dots in the key names. Rebuild the structure.
• Unique Values - easy - Duplicates are noise. Remove them.
• Validate Email - medium - Looks like an email. But is it?
• Value Count - easy - How many of each? Count them.
• Word Counter - easy - Words in, counts out.
• Zip to Record - easy - Two lists become one record.