CodeChef Count Substrings
Count Substrings |
All submissions for this problem are available.
Read problems statements in Mandarin Chinese and Russian.
Given a string S consisting of only 1s and 0s, find the number of substrings which start and end both in 1.
In this problem, a substring is defined as a sequence of continuous characters Si, Si+1, ..., Sj where 1 ≤ i ≤ j ≤ N.
Input
First line contains T, the number of testcases. Each testcase consists of N(the length of string) in one line and string in second line.
Output
For each testcase, print the required answer in one line.
Constraints
- 1 ≤ T ≤ 105
- 1 ≤ N ≤ 105
- Sum of N over all testcases ≤ 105
Example
Input: 2 4 1111 5 10001 Output: 10 3
存在任意两个数 gcd = 1 必然为n , 否则为 -1
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
#include <iostream> #include <cstdio> #include <algorithm> #include <cstring> #include <vector> #include <queue> using namespace std; const int N = 100010; int n , m , e[N] , ans ; inline int gcd( int a , int b ) { return b == 0 ? a : gcd(b,a%b); } int Run() { scanf("%d",&n); for( int i = 0 ; i < n ; ++i ) scanf("%d",&e[i]); sort( e , e + n ); for( int i = 1 ; i < n ; ++i ) if( gcd(e[0],e[i]) == 1 ) { return n; } return -1; } int main() { #ifdef LOCAL freopen("in","r",stdin); #endif ios::sync_with_stdio(0); int _ , cas = 1 ; scanf("%d",&_); while(_--) printf("%d\n",Run()); }
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