dict vs defaultdict vs Counter — The Three-Way Choice

The most-tested judgment call in junior DE dict interviews: which dict variant to reach for. Getting this right is a fluency signal. Getting it wrong — or not knowing defaultdict and Counter exist — is a yellow flag. Here's the exact decision framework interviewers want to see you apply. Plain dict — When Absence is Meaningful defaultdict — When You're Aggregating Counter — When You're Counting