摘要：
Problem Statement We have a grid with H rows and W columns. At first, all cells were painted white. Snuke painted N of these cells. The i-th ( 1≤i≤N ) 阅读全文
摘要：
Problem Statement You are given a string S consisting of digits between 1 and 9, inclusive. You can insert the letter + into some of the positions (po 阅读全文