Leimasin

#include <bits/stdc++.h>

#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()

using namespace std;
using ll = long long;

const int inf = 1e9;
const ll LLinf = 1e18;


int main() {
    cin.tie(0)->sync_with_stdio(0);
    int n, m, k;
    cin >> n >> m >> k;
    string s;
    cin >> s;

    vector<vector<int>> places(n + 1);
    vector<int> p(k);
    vector<int> op(n);

    for (int t = 0; t < k; ++t) {
        cin >> p[t];
        p[t]--;
        op[p[t]] = t;
        places[p[t]].push_back(t);
        places[p[t] + m].push_back(t);
    }

    vector<char> ans(n);
    set<int> active;

    for (int i = 0; i < n; ++i) {
        for (int x : places[i]) {
            if (active.count(x)) {
                active.erase(x);
            } else {
                active.insert(x);
            }
        }

        if (active.empty()) {
            ans[i] = '.';
        } else {
            int mx = *active.rbegin();
            // mx is some t
            // and we now p[t]
            // s[i - p[t]]
            ans[i] = s[i - p[mx]];
        }
    }

    for (char c : ans) {
        cout << c;
    }
    cout << "\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