BC # 32 1002 题意:给出一个数组 a 和一个数 K ,问是否存在数对( i , j ),使 a i - a i + 1 +……+ (-1)j - i a j : 对于这道题,一开始就想到了是前缀和,但是如果只是记录下前缀和数组,那么查找就会成为一个大问题.补题的时候一开始考虑用 hash 数组或者是 set 存,但是很明显 TLE 了,在翔神的推荐下,我研究了一下 hash表的创建过程,惊奇地发现,其实就是建了一个 HashMap 结构体,而里面放了这个表所用的数组以及相应操作…
题目链接:HDU 5183 Problem Description When given an array \((a_0,a_1,a_2,⋯a_{n−1})\) and an integer \(K\), you are expected to judge whether there is a pair \((i,j)(0≤i≤j<n)\) which makes that \(NP−sum(i,j)\) equals to \(K\) true. Here \(NP−sum(i,j)=a_i−…
Sequence II Time Limit: 9000/4500 MS (Java/Others) Memory Limit: 131072/131072 K (Java/Others)Total Submission(s): 849 Accepted Submission(s): 204 Problem Description Mr. Frog has an integer sequence of length n, which can be denoted as a1,a2,⋯…
题意: When given an array (a0,a1,a2,⋯an−1) and an integer K, you are expected to judge whether there is a pair (i,j)(0≤i≤j<n) which makes that NP−sum(i,j) equals to K true. Here NP−sum(i,j)=ai−ai+1+ai+2+⋯+(−1)j−iaj 1≤n≤1000000,−1000000000≤ai≤1000000000…
