1888A - Chemistry - CodeForces Solution

#include <bits/stdc++.h>
using namespace std;

int main(){
   int t;
   cin>>t;
   while(t--){
       int n,k;
       cin>>n>>k;
       string s;
       cin>>s;
       unordered_map<char,int> m;
       for(int i=0;i<n;i++){
           m[s[i]]++;
       }
       int even=0,odd=0;
       for(auto e:m){
           even+=(e.second/2)*2;
           if(e.second%2==1)odd++;
       }
       if(k>=odd-1)cout<<"YES"<<endl;
      
       else cout<<"NO"<<endl;
   }
    
}