#include<iostream> #include<cstdio> #include<cstring> #include<algorithm> #define N 500005 using namespace std; typedef long long LL; LL prefix[N], suffix[N], num[N]; LL cntSuf[N]; int main(){ int n; scanf("%d", &n);…

C. Number of Ways time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output You've got array a[1], a[2], ..., a[n], consisting of n integers. Count the number of ways to split all the elements of th…

You've got array a[1], a[2], ..., a[n], consisting of n integers. Count the number of ways to split all the elements of the array into three contiguous parts so that the sum of elements in each part is the same. More formally, you need to find the nu…

题目链接:5274. 停在原地的方案数 You have a pointer at index 0 in an array of size arrLen. At each step, you can move 1 position to the left, 1 position to the right in the array or stay in the same place (The pointer should not be placed outside the array at any…

题目如下: You have a pointer at index 0 in an array of size arrLen. At each step, you can move 1 position to the left, 1 position to the right in the array or stay in the same place  (The pointer should not be placed outside the array at any time). Given…

题意:给你n个数,在里面取4个数,可以重复取数,使和不超过M,求能得到的最大的数是多少: 思路:比赛时,和之前的一个题目很像,一直以为是体积为4(最多选择四次)的完全背包,结果并不是,两两求和,然后二分枚举; 完全背包是固定的体积,然后尽量使得装下的重量最大: 这个题目是固定的体积,但求在不超过该重量的情况下能得到的最大值. 至于为啥不是完全背包到现在还找到一个反例,以后再修改: 不过看到一共选择四次的时候,就应该想到是暴力... 比较相似的一个题目,12年的省赛题目:http://acm.sd…

Mine Number Time Limit: 1000ms   Memory limit: 65536K  有疑问?点这里^_^ 题目描述 Every one once played the game called Mine Sweeping, here I change the rule. You are given an n*m map, every element is a '*' representing a mine, or a '.' representing any other…

D. Number of Parallelograms 题目连接: http://www.codeforces.com/contest/660/problem/D Description You are given n points on a plane. All the points are distinct and no three of them lie on the same line. Find the number of parallelograms with the vertice…

Chess Placing time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output You are given a chessboard of size 1 × n. It is guaranteed that n is even. The chessboard is painted like this: "BWBW...BW"…

题目链接:http://codeforces.com/contest/768/problem/C 题意:给出n个数,k个操作,和一个x,每次操作先排序然后对奇数位数进行xor x操作,最后问k次操作后最大值和最小值 为多少. 题解:看似是要找规律的但是只要暴力就行了.主要是a[i]的范围就只有10的3次,而且时间还有4s,直接来一个vis[i]表示 0-2048个数内取了几个,这样排序都不用了.直接for 0-2048就行.(2的10次1024,异或2的9次就是,2的11次减1 所以设最大为20…