模拟：

1.https://atcoder.jp/contests/abc411/tasks/abc411_d

暴力枚举：

1.https://codeforces.com/contest/1985/problem/E

前缀和：

1.https://codeforces.com/contest/1985/problem/C

差分：

1.https://codeforces.com/contest/1985/problem/H1

前缀技巧：

1.https://codeforces.com/contest/1931/problem/D

2.https://codeforces.com/contest/2149/problem/D

二分：

1.https://codeforces.com/contest/2091/problem/D

2.https://codeforces.com/contest/2093/problem/E

3.https://codeforces.com/contest/2009/problem/E

4.https://codeforces.com/contest/2149/problem/F

5.https://codeforces.com/contest/1324/problem/D

双指针：

1.https://codeforces.com/contest/2106/problem/D

2.https://codeforces.com/contest/2149/problem/E

递归：

1.https://codeforces.com/contest/2093/problem/D

最大子数组和：

1.D – Flip to Gather

2.https://codeforces.com/contest/1692/problem/H

中位数：

1.https://codeforces.com/contest/2128/problem/E1

MEX：

1.https://codeforces.com/contest/2149/problem/C