Submission #1295695

#	Time	Username	Problem	Language	Result	Execution time	Memory
1295695		fairkrash	Bitaro the Brave (JOI19_ho_t1)	C++20	100 / 100	316 ms	151852 KiB

joi2019_ho_t1

#include <bits/stdc++.h>

using namespace std;
using ll = long long;
ll INF = 1e18;
ll MOD = 1e9 + 7;


int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    ll n, m;
    cin >> n >> m;
    vector<string> s(n);
    for (ll i = 0; i < n; i++) {
        cin >> s[i];
    }
    vector<vector<ll>> pref(n, vector<ll>(m + 1));
    for (ll i = 0; i < n; i++) {
        for (ll j = m - 1; j >= 0; j--) {
            pref[i][j] = pref[i][j + 1];
            if (s[i][j] == 'O') {
                pref[i][j]++;
            }
        }
    }
    vector<vector<ll>> dp(n, vector<ll>(m));
    for (ll j = 0; j < m; j++) {
        if (s[0][j] == 'J') {
            dp[0][j] = pref[0][j];
        }
    }
    for (ll j = 0; j < m; j++) {
        for (ll i = 1; i < n; i++) {
            dp[i][j] = dp[i - 1][j];
            if (s[i][j] == 'J') {
                dp[i][j] += pref[i][j];
            }
        }
    }
    ll ans = 0;
    for (ll i = 0; i < n; i++) {
        for (ll j = 0; j < m; j++) {
            if (s[i][j] == 'I') {
                ans += dp[i][j];
            }
        }
    }
    cout << ans;
}

• Subtask 1: 20 / 20
• Subtask 2: 30 / 30
• Subtask 3: 50 / 50