1427B - Chess Cheater - CodeForces Solution

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

// Macros definition
#define ll long long
#define vi vector<ll>
#define vvi vector<vector<ll>>
#define ln cout<<"\n";
#define print(a) cout<< a << ' '

// Predefined values
ll mod = 1e9+7;

void solve(){
    ll n,k;
    cin>>n>>k;
    string s;
    cin>>s;
    ll w=0;
    for(char c : s){
        w += (c=='W');
    }
    if(w==0){
        k=min(k,n);
        print(max(0ll,2*k-1));
        ln;
        return;
    }
    w += k;
    if(w>=n){
        print(2*n-1);
        ln;
        return;
    }
    vector<ll>v;
    int l=0;
    for(int i=0; i<n; i++){
        if(s[i]=='L') l++;
        else{
            v.push_back(l);
            l=0;
        }
    }
    if(l>0) v.push_back(l);
    if(s[0]=='L'){
        v.erase(v.begin());
    }
    if(s.back()=='L') v.pop_back();
    sort(v.begin(), v.end());
    ll cnt=0, i=0;
    while(i<v.size()){
        if(cnt+v[i]>k) break;
        cnt += v[i];
        i++;
    }
    int x=v.size()-i;
    print(2*w-1-x);
    ln;
}

int main(){

    // Deepu Yadav
    ios_base :: sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    int t=1;
    cin>>t;
    while(t--){
        solve();
    }
    return 0;
}