题目 | Even Subarrays
Codeforces Round #841 (Div. 2) and Divide by Zero 2022
C. Even Subarrays
算法 | 前缀和、差分
原数组：$[3,1,4,1,5,9]$
前缀和：$[3,4,8,9,14,23]$
差分：$[3,-2,3,-3,4,4]$
题目 | Operations on a Matrix.md
NOMURA Programming Contest 2022（AtCoder Beginner Contest 253）
F - Operations on a Matrix
题目 | RLE
Monoxer Programming Contest 2022（AtCoder Beginner Contest 249）
E - RLE