Leimasin

#include <iostream>
#include <string>
#include <utility>
#include <vector>
using namespace std;
using pii = pair<int,int>;

int main() {
    cin.tie(0)->sync_with_stdio(0);
    int n,m,k; cin>>n>>m>>k;
    string P; cin>>P;
    vector<int> x(n);
    for (int i=1; i<=k; i++) {
        int pos; cin>>pos;
        x[pos-1] = i;
    }
    vector<pii> Q(n+1);
    int L=0, R=0;
    string ans;
    for (int i=0; i<n; i++) {
        while (L<R && i - Q[L].second >= m)
            L++;
        if (x[i]) {
            while (L<R && Q[R-1].first < x[i])
                R--;
            Q[R++] = {x[i],i};
        }
        if (L==R) ans += '.';
        else ans += P[i - Q[L].second];
    }
    cout << ans << '\n';
}

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 1, 2, 3

Verdict: ACCEPTED

Test 3

Group: 1, 2, 3

Verdict: ACCEPTED

Test 4

Group: 1, 2, 3

Verdict: ACCEPTED

Test 5

Group: 2, 3

Verdict: ACCEPTED

Test 6

Group: 2, 3

Verdict: ACCEPTED

Test 7

Group: 2, 3

Verdict: ACCEPTED

Test 8

Group: 2, 3

Verdict: ACCEPTED

Test 9

Group: 3

Verdict: ACCEPTED

Test 10

Group: 3

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED