siyu

Laboratory Work 传送门 题意:给你一个长为n的序列，该序列的元素之间的差值不超过二，现在要你找出一个新的大小同为n的序列，其平均数于原序列相等，并且里面的元素大小要在原序列的范围之内。 思路:要求大小为n，平均数相等，元素大小范围在原序列内，这说明要求在原序列中元素之间进行转化，而能转化的只有一种—a+1 + a+3 = 2*（a+2） 所以进行判断转化就可以了 ...

Mystical Mosaic There is a rectangular grid of n rows of m initially-white cells each. Arkady performed a certain number (possibly zero) of operations on it. In the i-th operation, a non-empty subse...

Chessboard Magnus decided to play a classic chess game. Though what he saw in his locker shocked him! His favourite chessboard got broken into 4 pieces, each of size n by n, n is always odd. And what...

32. Longest Valid Parentheses 传送门 dp思路： 问题->最长有效括号子序列长度 状态->dp[i]以i为结尾的最长有效括号子序列长度(则str[i]= ‘)’ ); 子状态: 如果str[i-1]= ‘(’ ---->dp[i-2] 如果str[i-1]= ‘)’ ---->如果str[i-dp[i-1]-1]= ‘(’ --...