Week 5: Searching (練習題) = [CODEFORCES 1131C Birthday](https://codeforces.com/contest/1131/problem/C) [CODEFORCES 1042A Benches](https://codeforces.com/contest/1042/problem/A) [CODEFORCES 919B Perfect Number](https://codeforces.com/contest/919/problem/B) [CODEFORCES 978C Letters](https://codeforces.com/contest/978/problem/C) [CODEFORCES 1138A Sushi for Two](https://codeforces.com/contest/1138/problem/A) [CODEFORCES 750A New Year and Hurry](https://codeforces.com/contest/750/problem/A) [CODEFORCES 888C K-Dominant Character](https://codeforces.com/contest/888/problem/C) [CODEFORCES 1099B Squares and Segments](https://codeforces.com/contest/1099/problem/B) [CODEFORCES 706B Interesting drink](https://codeforces.com/contest/706/problem/B) \* [CODEFORCES 1117C Magic Ship](https://codeforces.com/contest/1117/problem/C)