A.cpp

#include<bits/stdc++.h>
using namespace std;
#define fo(i,n) for(i=0;i<n;i++)
#define fo2(i,start,end) for(i=start;i<=end;i++)
#define rfo(i,n) for(i=n-1;i>=0;i--)
#define lli long long int
#define deb(x) cout<<#x<<"="<<x<<endl
#define deb2(x,y) cout<<#x<<"="<<x<<","<<#y<<"="<<y<<endl
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define tr(it,a) for(auto it=a.begin(); it!=a.end();it++)
#define nl '\n'
#define PI 3.141592653589793238
#define mod 1000000007

void solve(){
    int i,j;
    int n,k,count=0,last_i,last_j;
    cin>>n>>k;
    string s,a,b,temp;
    cin>>s;
    if(k==0){
        cout<<"YES\n";
        return;
    }
    if(2*k==n){
        cout<<"NO\n";
        return;
    }
    i=0; j=n-1;
    while(i<j && s[i]==s[j]){
        i++; 
        j--;
    }
    if(i>=k){
        cout<<"YES\n";
    }
    else{
        cout<<"NO\n";
    }
}

int main(){
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    int t=1;
    cin>>t;
    while(t--){
        solve();
    }
    return 0;
}