Leimasin

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

using ll=long long;
using vl=vector<ll>;
#define all(c) begin(c),end(c)
#define pb push_back
#define sz(c) ll((c).size())

#define FOR(i,a,b) for(ll i=(a);i<(b);i++)

#define TR(x) ({ if(1) cout << __LINE__ << ": " #x " = " << (x) << endl; })

// Only when needed
using dd = double;
const dd eps = 1e-10;
using vd = vector<dd>;
using vvd = vector<vd>;

using vvl = vector<vl>;

int main(int argc, char const *argv[])
{
    cin.sync_with_stdio(0);
    cin.tie(0);

    ll n, m, k; 
    cin >> n >> m >> k;

    string stamp; cin >> stamp;
    vl last(n, -1), rem(n + 1, -1);
    FOR(i, 0, k){
        ll x; cin >> x;
        x--;
        last[x] = i;
        rem[x + m] = i;
    }
    map<ll, ll, greater<>> t_pos;
    string res(n, '.');
    FOR(i, 0, n){
        if(last[i] != -1){
            t_pos[last[i]] = i;
        }
        if(rem[i] != -1){
            t_pos.erase(rem[i]);
        }
        if(!t_pos.empty()){
            ll beg = t_pos.begin()->second;
            res[i] = stamp[i - beg];
        }
    }
    cout << res << "\n";


    return 0;
}

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