Complement Search (Two Sum Pattern) Problems
13 Complement Search (Two Sum Pattern) problems on LeetCode, a Arrays & Hashing interview pattern, ranked by importance (how often it comes up in real interviews). Difficulty (ELO) and importance shown per problem.
| # | PROBLEM | DIFF | ELO | IMP | PATTERNS |
|---|---|---|---|---|---|
| 1 | Two Sum | Easy | 1142 | 95 | Frequency Counting / Hash Map Lookup |
| 2 | Max Number of K-Sum Pairs | Easy | 1346 | 78 | Opposite-Direction (Converging) · Frequency Counting / Hash Map Lookup |
| 3 | 4Sum II | Easy | 1372 | 72 | Frequency Counting / Hash Map Lookup |
| 4 | Count Pairs That Form a Complete Day II | Easy | 1385 | 68 | Frequency Counting / Hash Map Lookup · Modular Arithmetic |
| 5 | Pairs of Songs With Total Durations Divisible by 60 | Easy | 1377 | 62 | Modular Arithmetic |
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