Submission #1310028

#	Time	Username	Problem	Language	Result	Execution time	Memory
1310028		syanvu	JJOOII 2 (JOI20_ho_t2)	C++20	0 / 100	0 ms	332 KiB

ho_t2

// #pragma optimize ("g",on)
// #pragma GCC optimize ("inline")
// #pragma GCC optimize ("Ofast")
// #pragma GCC optimize ("unroll-loops")
// #pragma GCC optimize ("03")
#include <bits/stdc++.h>

#define pb push_back
#define SS ios_base::sync_with_stdio(0);cin.tie(nullptr);cout.tie(nullptr);
#define int long long
#define all(v) v.begin(),v.end()
using namespace std;
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());

const int N = 5e5 + 1, inf = 1e9, mod = 998244353;

void solve(){
    int n, k;
    cin >> n >> k;
    string s;
    cin >> s;
    s = '!' + s;
    int ans = 0, cnt = 0, l = 1, r = n;
    for(int i = 1; i <= n; i++){
        if(cnt == k) break;
        l = i;
        if(s[i] == 'J'){
            cnt++;
        }
        else{
            ans += (cnt > 0);
        }
    }
    if(cnt != k){
        cout << -1 << '\n';
        return;
    }
    cnt = 0;
    for(int i = n; i >= 1; i--){
        if(cnt == k) break;
        r = i;
        if(s[i] == 'I'){
            cnt++;
        }
        else{
            ans += (cnt > 0);
        }
    }
    if(cnt != k){
        cout << -1 << '\n';
        return;
    }
    cnt = 0;
    for(int i = l + 1; i < r; i++){
        if(s[i] != 'O') ans++;
        else{
            if(cnt == k) ans++;
            else cnt++;
        }
    }
    if(cnt != k){
        cout << -1 << '\n';
        return;
    }
    cout << ans << '\n';
}

signed main(){
    SS
    // freopen("trains.in", "r", stdin);
    // freopen("trains.out", "w", stdout);

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

• Subtask 1: 0 / 1
• Subtask 2: 0 / 12
• Subtask 3: 0 / 87