Codeforces Round #713 (Div. 3) Editorial 记录一下自己写的前二题本人比较菜 A. Spy Detected! You are given an array a consisting of n (n≥3) positive integers. It is known that in this array, all the numbers except one are the same (for example, in the array [4,11,4,4]…
D. Dynamic Problem Scoring time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Vasya and Petya take part in a Codeforces round. The round lasts for two hours and contains five problems. For th…
题目链接:http://www.codeforces.com/problemset/problem/327/A题意:你现在有n张牌,这些派一面是0,另一面是1.编号从1到n,你需要翻转[i,j]区间的牌一次,使得看到的牌是1的数量最大.C++代码: #include <iostream> using namespace std; ; int n, a[maxn], sum[maxn]; int flip(int L, int R) { ]; - a1; //cout << &quo…
在div 188中,幸运的达成了这学期的一个目标:CF1800+,所以这次可以打星去做div2,有点爽. A.Flipping Game 直接枚举 B. Hungry Sequence 由于素数的分布大概10个中有一个,所以直接筛法筛1e5个即可. C. Magic Five 删除串s中的某些字符,使得他整除5,并且跟删除顺序有关,现在问有k个串s连在一起组成一个新的串,问新的串有多少种删除方式. 我们可以先看每一个串,由于整除5的数的末尾只能为0或者5. 用样例二 13990作为说明. 考虑只…