摘要：
Polycarp wants to assemble his own keyboard. Layouts with multiple rows are too complicated for him — his keyboard will consist of only one row, where 阅读全文
摘要：
Your company was appointed to lay new asphalt on the highway of length nn. You know that every day you can either repair one unit of the highway (lay 阅读全文
摘要：
You are given a string ss. Each character is either 0 or 1. You want all 1's in the string to form a contiguous subsegment. For example, if the string 阅读全文