题意:给你一个由'('和')'组成的字符串,问你有多少个子串,前半部分是由'('组成后半部分由')'组成 思路:枚举这个字符串中的所有'('左括号,它左边的所有'('左括号的个数为num1,它的右边的所有')'右括号的个数为num2, 根据范德蒙恒等式计算得出 代码: #include <bits/stdc++.h> #define ll long long #define maxn 200000 #define mod 1000000007 using namespace std; ll j…

题意:有一个小朋友,即喜欢下象棋,还喜欢编程,于是他打算上这两种课的兴趣班,这两种课有着不同的上课时间,他想让两堂课之间的休息时间最多,问最大时间是多少 思路:看到这道题的第一反应就是贪心,于是用结构体排个序然后再暴力枚举....果断超时了,其实只要找两个区间差最远的就可以了 代码: #include <bits/stdc++.h> #define inf 1e9 using namespace std; int main() { int l1,r1,l2,r2; l1=;r1=inf; l2…

D. Anton and School - 2 题目连接: http://codeforces.com/contest/785/problem/D Description As you probably know, Anton goes to school. One of the school subjects that Anton studies is Bracketology. On the Bracketology lessons students usually learn differ…

题目链接:http://codeforces.com/contest/785 A. Anton and Polyhedrons time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Anton's favourite geometric figures are regular polyhedrons. Note that there…

Anton and School - 2 题解: 枚举每个左括号作为必选的. 那么方案数就应该是下面的 1 , 然后不断化简, 通过范德蒙恒等式 , 可以将其化为一个组合数. 代码: #include<bits/stdc++.h> using namespace std; #define Fopen freopen("_in.txt","r",stdin); freopen("_out.txt","w",stdou…

C. Anton and Fairy Tale 题目连接: http://codeforces.com/contest/785/problem/C Description Anton likes to listen to fairy tales, especially when Danik, Anton's best friend, tells them. Right now Danik tells Anton a fairy tale: "Once upon a time, there liv…

B. Anton and Classes 题目连接: http://codeforces.com/contest/785/problem/B Description Anton likes to play chess. Also he likes to do programming. No wonder that he decided to attend chess classes and programming classes. Anton has n variants when he wil…

A - Anton and Polyhedrons 题目连接: http://codeforces.com/contest/785/problem/A Description Anton's favourite geometric figures are regular polyhedrons. Note that there are five kinds of regular polyhedrons: Tetrahedron. Tetrahedron has 4 triangular face…

E. Anton and Permutation time limit per test 4 seconds memory limit per test 512 megabytes input standard input output standard output Anton likes permutations, especially he likes to permute their elements. Note that a permutation of n elements is a…

题目链接 转自 给你一个字符串问你能构造多少RSBS. #include<bits/stdc++.h> #define LL long long #define fi first #define se second #define mp make_pair #define pb push_back using namespace std; LL gcd(LL a,LL b){return b?gcd(b,a%b):a;} LL lcm(LL a,LL b){return a/gcd(a,b)*…