杭电5672

Problem Description

There is a string  S . S  only contain lower case English character. (10≤length(S)≤1,000,000)
How many substrings there are that contain at least  k(1≤k≤26)  distinct characters?

 

Input

There are multiple test cases. The first line of input contains an integer  T(1≤T≤10)  indicating the number of test cases. For each test case:

The first line contains string  S .
The second line contains a integer  k(1≤k≤26) .

 

Output

For each test case, output the number of substrings that contain at least  k  dictinct characters.

 

Sample Input

   
   
   
   

    
    
    
    2
abcabcabca
4
abcabcabcabc
3
   
   
   
   

 

Sample Output

   
   
   
   

    
    
    
    0
55
   
   
   
   

 

#include<iostream>
#include<cstdio>
#include<queue>
#include<cstring>
#include<cmath>
#include<cstdlib>
using namespace std;
char ch[1000005];
int vis[200];
int main(){
    int t;
    cin>>t;
    while(t--){
        scanf("%s",ch);
        int k;
        scanf("%d",&k);
        long long ans=0;
        memset(vis,0,sizeof(vis));
        int sum=1,len=strlen(ch),l=0,r=0;
        vis[ch[l]]++;
        if(sum>=k)ans+=len-r;
        for(int i=1;i<len;i++){
            if(!vis[ch[i]])sum++;
            vis[ch[i]]++;
            r=i;
            while(sum>=k){
                ans+=len-i;
                vis[ch[l]]--;
                if(!vis[ch[l]])sum--;
                l++;
            }
        }
        cout<<ans<<endl;
    }
    return 0;
}