Submission #617757

#	Time	Username	Problem	Language	Result	Execution time	Memory
617757		bebra	Bitaro the Brave (JOI19_ho_t1)	C++17	100 / 100	82 ms	54288 KiB

joi2019_ho_t1

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


int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int h, w;
    cin >> h >> w;
    vector<string> t(h);
    for (auto& s : t) {
        cin >> s;
    }
    vector<vector<int>> pref_vert(h, vector<int>(w));
    long long ans = 0;
    for (int i = h - 1; i >= 0; --i) {
        vector<int> pref_hor(w);
        pref_hor[w - 1] = t[i].back() == 'O';
        for (int j = w - 2; j >= 0; --j) {
            if (t[i][j] == 'J') {
                ans += (long long)pref_hor[j + 1] * (i + 1 < h ? pref_vert[i + 1][j] : 0);
            }
            pref_hor[j] = pref_hor[j + 1] + (t[i][j] == 'O');
            pref_vert[i][j] = t[i][j] == 'I';
            if (i + 1 < h) {
                pref_vert[i][j] += pref_vert[i + 1][j];
            }
        }
    }
    cout << ans << '\n';
    
    return 0;
}

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