B. Hamming Distance Sum time limit per test: 2 seconds memory limit per test:256 megabytes input: standard input output: standard output Genos needs your help. He was asked to solve the following programming problem by Saitama: The length of some str…

B. Hamming Distance Sum 题目连接: http://www.codeforces.com/contest/608/problem/A Description Genos needs your help. He was asked to solve the following programming problem by Saitama: The length of some string s is denoted |s|. The Hamming distance betw…

B. Hamming Distance Sum   Genos needs your help. He was asked to solve the following programming problem by Saitama: The length of some string s is denoted |s|. The Hamming distance between two strings s and t of equal length is defined as , where si…

前缀和思想 Genos needs your help. He was asked to solve the following programming problem by Saitama: The length of some string s is denoted |s|. The Hamming distance between two strings s and t of equal length is defined as , where si is the i-th charact…

Genos needs your help. He was asked to solve the following programming problem by Saitama: The length of some string s is denoted |s|. The Hamming distance between two strings s and t of equal length is defined as , where si is the i-th character of…

题目: http://codeforces.com/contest/608/problem/B 字符串a和字符串b进行比较,以题目中的第一个样例为例,我刚开始的想法是拿01与00.01.11.11从左到右挨个比较,希望能找到一些规律,结果并没有... 其实,如果我们能从整个比较过程来看这个问题,整个过程就没有那么难.题目要求的东西,其实就是a字符串和b字符串子串每次比较的不同的个数的总和,当我们像上面那个思路,拿a字符串每次移动一位,和b进行比较的时候,从整个过程来看,就相当于a的每一个元素从前…

题目链接:http://codeforces.com/problemset/problem/608/B 题目意思:给出两个字符串 a 和 b,然后在b中找出跟 a 一样长度的连续子串,每一位进行求相减的绝对值然后相加(这个讲得有点绕),直接举个例子就很容易理解了. 假设a = 01,b = 00111, 符合条件的b的子串有:00, 01, 11, 11 然后: |01-00| = |0-0| + |1-0| = 1,  |01-01| = |0-0| + |1-1| = 0, |01-11|…

洛谷 Codeforces bzoj1,bzoj2 这可真是一道n倍经验题呢-- 思路 我首先想到了DP,然后矩阵,然后线段树,然后T飞-- 搜了题解之后发现是模拟费用流. 直接维护选k个子段时的最优解似乎也可以做,然而复杂度是O(nk2logn),显然跑不过. 考虑一种费用流做法.序列里每个点拆成入点和出点,源连入汇连出,入点和出点间连流量1费用ai的边,相邻点出点向入点连流量1费用0的边,整体限流k. 直接跑当然还不如暴力.观察一下这个做法是在干啥:每次选择费用最大的一段,然后利用反向边将这…

题目链接 (BZOJ) https://www.lydsy.com/JudgeOnline/problem.php?id=3836 (Codeforces) http://codeforces.com/contest/280/problem/D 题解 似乎是最广为人知的模拟费用流题目. 线段树维护DP可以做,但是合并的复杂度是\(O(k^2)\), 会TLE. 考虑做\(k\)次费用流,很容易建出一个图,中间的边容量都是1,求的是最大费用. 做费用流的过程,我们每次找一条最长路,然后将其增广,增…

  B. Hamming Distance Sum   time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Genos needs your help. He was asked to solve the following programming problem by Saitama: The length of some st…