Leimasin

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

void testCase() {

}

int p[500005];
char res[1000002];
set<int> ss;
 
int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    /*
    int t;
    cin >> t;
    for (int i = 0; i < t; i++) {
        testCase();
    }
    */
    int n, m, k;
    cin >> n >> m >> k;
    string s;
    cin >> s;
    for (int i = 0; i < k; i++) cin >> p[i];
    for (int i = 1; i <= n; i++) res[i] = '.';
    for (int i = k-1; i >= 0; i--) {
        int start = p[i];
        int goal = start + m - 1;
        for (int j = start; j <= goal; j++) {
            if (res[j] != '.') break;
            res[j] = s[j-p[i]];
        }
        auto it = ss.lower_bound(start);
        while (it != ss.end() && *it <= goal) {
            start = *it + 1;
            auto it2 = it;
            it++;
            ss.erase(it2);
        }
        for (int j = start; j <= goal; j++) {
            if (res[j] != '.') break;
            res[j] = s[j-p[i]];
        }
        ss.insert(goal);
    }
    for (int i = 1; i <= n; i++) cout << res[i];
    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