2018ICPC南京网络赛 A. An Olympian Math Problem 题目描述:求\(\sum_{i=1}^{n} i\times i! \%n\) solution \[(n-1) \times (n-1)! \% n= (n-2)!(n^2-2n+1) \%n =(n-2)!\] \[(n-2+1)\times (n-2)! \% n= (n-3)!(n^2-3n+2) \%n =(n-3)! \times 2\] 以此类推,最终只剩下\(n-1\) 时间复杂度:\(O(1)\…

题意: n道题,每道题有ai和bi,完成这道题需要先完成若干道题,完成这道题可以得到分数t*ai+bi,其中t是时间 1s, n<=20 思路: 由n的范围状压,状态最多1e6 然后dfs,注意代码中dfs里的剪枝, 对一个状态statu,因为贪心的取最大值就行,所以及时剪枝 代码: 当时写不出来真是菜的活该 #include<iostream> #include<cstdio> #include<algorithm> #include<cmath>…

题意: 有向图,可以把k条路的长度变为0,求1到n的最短路 思路: 将图复制k份,一共k+1层图,对于每一条i→j,都连一条低层的i→高层的j,并且权值为0 即对每一对<i,j,w>,都加边<i,j,w>,<i+n,j+n,w>,<i+2n,j+2n,w>,....,<i+kn,j+kn,w> 同时加“楼梯”<i,j+n,0>,<i+n,j+2n,0>,...,<i+(k-1)n, j+kn> 然后跑一个1~(…

Divide Groups Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 423    Accepted Submission(s): 161 Problem Description   This year is the 60th anniversary of NJUST, and to make the celebration mor…

Count The Pairs Time Limit: 20000/10000 MS (Java/Others)    Memory Limit: 65535/65535 K (Java/Others)Total Submission(s): 277    Accepted Submission(s): 150 Problem Description   With the 60th anniversary celebration of Nanjing University of Science…

Walk Through Squares Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65535/65535 K (Java/Others)Total Submission(s): 200    Accepted Submission(s): 57 Problem Description   On the beaming day of 60th anniversary of NJUST, as a military colleg…

2019ICPC南京网络赛A题 The beautiful values of the palace https://nanti.jisuanke.com/t/41298 Here is a square matrix of n * nn∗n, each lattice has its value (nn must be odd), and the center value is n * nn∗n. Its spiral decline along the center of the squar…

南京网络赛自闭现场 https://nanti.jisuanke.com/t/41298 二维偏序经典题型 二维前缀和!!! #include<bits/stdc++.h> using namespace std; #define int long long #define sc(x) scanf("%lld",&x); int T; #define P pair<int,int> #define fi first #define se second #…

题目链接 题意 : 给出一个由数字组成的字符串.然后要你找出其所有本质不同的回文子串.然后将这些回文子串转化为整数后相加.问你最后的结果是多少.答案模 1e9+7 分析 : 应该可以算是回文树挺裸的题目吧 可惜网络赛的时候不会啊.看着马拉车想半天.卒... 对于每一个节点.记录其转化为整数之后的值 然后在回文串插入字符的时候 不断维护这个信息就行了 其实很好理解.看一下代码就懂了 ( 如果你学过回文树的话... ) 就是多加了变量 val .维护语句 #include<bits/stdc++.h…

30.43% 2000ms 262144K Feeling hungry, a cute hamster decides to order some take-away food (like fried chicken for only 3030 Yuan). However, his owner CXY thinks that take-away food is unhealthy and expensive. So she demands her hamster to fulfill a m…