Submission #1267331

#	Time	Username	Problem	Language	Result	Execution time	Memory
1267331		gay	JJOOII 2 (JOI20_ho_t2)	C++20	100 / 100	16 ms	5332 KiB

ho_t2

#include <bits/stdc++.h>
#include <experimental/random>
#include <random>

using namespace std;
using ll = long long;
using ld = long double;

const ll INF = 1e18, MOD = 998244353;

void solve();

signed main() {
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    ll q = 1;
    //cin >> q;
    while (q--) {
        solve();
    }
}

void solve() {
    ll n, k;
    cin >> n >> k;
    string s;
    cin >> s;
    vector<ll> p1(n + 1), p2(n + 1), p3(n + 1);
    for (int i = 0; i < s.size(); i++) {
        p1[i + 1] = p1[i], p2[i + 1] = p2[i], p3[i + 1] = p3[i];
        if (s[i] == 'J') {
            p1[i + 1]++;
        }
        if (s[i] == 'O') {
            p2[i + 1]++;
        }
        if (s[i] == 'I') {
            p3[i + 1]++;
        }
    }

    ll ans = INF;
    for (int i = 0; i < n; i++) {
        ll st = i;
        if (s[st] != 'J') {
            continue;
        }
        ll cnt = 0;


        ll l = st - 1, r = n - 1;
        if (p1[n] - p1[st] < k) {
            continue;
        }
        while (r - l > 1) {
            ll mid = (l + r) / 2;
            if (p1[mid + 1] - p1[st] >= k) {
                r = mid;
            } else {
                l = mid;
            }
        }
        cnt += r - st - k + 1;
        st = r + 1;

        l = st - 1, r = n - 1;
        if (p2[n] - p2[st] < k) {
            continue;
        }
        while (r - l > 1) {
            ll mid = (l + r) / 2;
            if (p2[mid + 1] - p2[st] >= k) {
                r = mid;
            } else {
                l = mid;
            }
        }
        cnt += r - st - k + 1;
        st = r + 1;

        l = st - 1, r = n - 1;
        if (p3[n] - p3[st] < k) {
            continue;
        }
        while (r - l > 1) {
            ll mid = (l + r) / 2;
            if (p3[mid + 1] - p3[st] >= k) {
                r = mid;
            } else {
                l = mid;
            }
        }
        cnt += r - st - k + 1;
        ans = min(ans, cnt);
    }

    if (ans == INF) {
        cout << -1;
    } else {
        cout << ans;
    }
}

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