- DFS
https://atcoder.jp/contests/abc236/tasks/abc236_d diff1190
https://atcoder.jp/contests/abc220/tasks/abc220_f diff1304
https://atcoder.jp/contests/abc222/tasks/abc222_e diff1491
https://atcoder.jp/contests/abc239/tasks/abc239_e diff1084
- BFS
https://atcoder.jp/contests/abc224/tasks/abc224_d diff1376
- 二分探索
https://atcoder.jp/contests/zone2021/tasks/zone2021_c diff1497
- 個数無制限DP
https://atcoder.jp/contests/abc153/tasks/abc153_e diff1015
- 圧縮DP
https://atcoder.jp/contests/abc232/tasks/abc232_e diff1380
- 毛DP
https://atcoder.jp/contests/abc233/tasks/abc233_e diff969
https://atcoder.jp/contests/abc135/tasks/abc135_d diff1334
https://atcoder.jp/contests/abc155/tasks/abc155_e diff1569
- 桁DP
https://atcoder.jp/contests/abc154/tasks/abc154_e diff1298
- 平面走査
https://atcoder.jp/contests/abc245/tasks/abc245_e diff1571
- 数学
https://atcoder.jp/contests/arc123/tasks/arc123_a diff177
https://atcoder.jp/contests/abc230/tasks/abc230_e diff969
https://atcoder.jp/contests/abc114/tasks/abc114_d diff1337
- 半分全列挙
https://atcoder.jp/contests/abc074/tasks/arc083_a diff1255
- 時系列処理
https://atcoder.jp/contests/abc233/tasks/abc233_d diff726
https://atcoder.jp/contests/abc235/tasks/abc235_e diff1304
- 2変数（3変数）からの確定
https://atcoder.jp/contests/arc069/tasks/arc069_b diff1344
https://atcoder.jp/contests/abc238/tasks/abc238_e diff1577
- 集合の性質
https://atcoder.jp/contests/agc055/tasks/agc055_a diff1348
- マンハッタン距離は45度回転