摘要:
Description You are given a string s consisting only of characters 0 and 1. A substring [l, r] of s is a string slsl + 1sl + 2... sr, and its length e 阅读全文
摘要:
Description There are N cities in a country, and there is one and only one simple path between each pair of cities. A merchant has chosen some paths a 阅读全文