题目链接: Problem - B - Codeforces 题目 Example input 4 3 1 1 1 5 1 2 3 4 5 5 0 2 0 3 0 4 1 3 5 1 output 6 0 36 4 题意 给一串数,用这n个数排几种序列,使得 i=1~(n-1) 输出有几种序列满足情况 题解 附  : & -- 位运算之一,有0则0 不用怀疑,一堆数&完后,得到的数<=这堆数的任意一个数 因为每一位只要有一个数==0,这一位就=0,否则为1 记最后&完所有数的…

Codeforces Round #609 (Div. 2)前五题题解 补题补题…… C题写挂了好几个次,最后一题看了好久题解才懂……我太迟钝了…… 然后因为longlong调了半个小时…… A.Equation 题目大意:有一个数字n,让你给出任意两个合数a,b满足a - b = n. 我们知道大于2的偶数都是合数,那么如果n为奇数,只要n加上一个奇数合数一定也为合数,如果n为偶数,那么n加上一个偶数合数也一定为合数. 因为只求任意一组,就直接选择4,9,若为奇数输出 +n 和9,偶数输出 +…

地址:http://codeforces.com/contest/768/problem/D 题目: D. Jon and Orbs time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Jon Snow is on the lookout for some orbs required to defeat the white wal…

地址:http://codeforces.com/contest/768/problem/C 题目: C. Jon Snow and his Favourite Number time limit per test 4 seconds memory limit per test 256 megabytes input standard input output standard output Jon Snow now has to fight with White Walkers. He has…

地址:http://codeforces.com/contest/768/problem/B 题目: B. Code For 1 time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Jon fought bravely to rescue the wildlings who were attacked by the white-w…

地址:http://codeforces.com/problemset/problem/768/A 题目: A. Oath of the Night's Watch time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output "Night gathers, and now my watch begins. It shall not end…

C题卡了好久,A掉C题之后看到自己已经排在好后面说实话有点绝望,最后又过了两题,总算稳住了. AC:ABCDE Rank:191 Rating:2156+37->2193 A.Oath of the Night's Watch 题目大意:给定N个数,求有多少个数存在严格比它大的数和严格比它小的数.(N<=100,000) 思路:阅读能力训练+手速,排序一遍就没了. #include<cstdio> #include<cstring> #include<algori…

思路:把边看成点,然后每条边只能从下面的边转移过来,我们将边按照u为第一关键字,w为第二关键字排序,这样就能用线段树维护啦. #include<bits/stdc++.h> #define LL long long #define fi first #define se second #define mk make_pair #define pii pair<int,int> using namespace std; ; + ; const int inf = 0x3f3f3f3f…

A. Oath of the Night's Watch time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output "Night gathers, and now my watch begins. It shall not end until my death. I shall take no wife, hold no lands,…

打表找规律即可. 1,1,2,2,2,3,3,3,3,4,4,4,4,4... 注意打表的时候,sg值不只与剩下的石子数有关,也和之前取走的方案有关. //#include<cstdio> //#include<set> //#include<cstring> //using namespace std; //bool vis[16]; //int n,SG[16][1<<16]; //int sg(int x,int moved) //{ // if(SG…