题意: 有n个数字, 要求在这n个数中选出至少两个数字, 使得它们的和在L,R之间,并且最大的与最小的差值要不小于x 思路: 撒比了啊... 根据状态的话一共也就是2^15-直接暴力,二进制的小魅力还是没能领会: code-- #include <bits/stdc++.h> #include<algorithm> using namespace std; typedef long long LL; const int N=1e6+10; int a[20]; int main()…

[题目链接]:click here~~ [题目大意] 一组题目的数目(n<=15),每一个题目有对应的难度,问你选择一定的题目(大于r个且小于l个)且选择后的题目里最小难度与最大难度差不小于x,求选择方案数. [解题思路]: DFS+回溯. 先发一发比較拙的代码: #include <bits/stdc++.h> using namespace std; const int N=1e5+10; int num[N],mum[N]; int n,m,q,t,l,r; int top,ans…

今天,开博客,,,激动,第一次啊 嗯,,先来发水题纪念一下 D1. Magic Powder - 1   This problem is given in two versions that differ only by constraints. If you can solve this problem in large constraints, then you can just write a single solution to the both versions. If you fin…

Adieu l'ami. Koyomi is helping Oshino, an acquaintance of his, to take care of an open space around the abandoned Eikou Cram School building, Oshino's makeshift residence. The space is represented by a rectangular grid of n × m cells, arranged into n…

Rock... Paper! After Karen have found the deterministic winning (losing?) strategy for rock-paper-scissors, her brother, Koyomi, comes up with a new game as a substitute. The game works as follows. A positive integer n is decided first. Both Koyomi a…

It's hard times now. Today Petya needs to score 100 points on Informatics exam. The tasks seem easy to Petya, but he thinks he lacks time to finish them all, so he asks you to help with one.. There is a glob pattern in the statements (a string consis…

Polycarp watched TV-show where k jury members one by one rated a participant by adding him a certain number of points (may be negative, i. e. points were subtracted). Initially the participant had some score, and each the marks were one by one added…

传送门:https://codeforces.com/contest/691/problem/F 题意:给你n个数和q次询问,每次询问问你有多少对ai,aj满足ai*aj>=q[i],注意 a*b 与 b*a是不同的 题解:sum[i]记录的是两个数乘积为i的方法数,然后前缀和记录小于等于乘积为i的方法个数,输出答案就容斥一下,因为n个数最多组成n*(n-1)/2对数,减去小于乘积为q[i]的数后即为乘积大于等于q[i]的方法个数 为什么可以暴力是因为注意到了值域的范围为3e6,调和级数的复杂度…

题目链接 题意: 给定一个字符串,最多更改一个字符,问最多可以有多少个“VK”子串? 思路: 由于数据量很小,不妨尝试暴力写.首先算出不更改任何字符的情况下有多个VK字串,然后尝试每一次更改一个位置的字符,然后暴力算出有多少个VK,取出这些答案中 的最大值,即是答案. 代码: #include <iostream> #include <cstdio> #include <cstring> #include <algorithm> #include <c…

http://codeforces.com/problemset/problem/548/B Mike and some bears are playing a game just for fun. Mike is the judge. All bears except Mike are standing in an n × m grid, there's exactly one bear in each cell. We denote the bear standing in column n…