Submission #1280152

#	Time	Username	Problem	Language	Result	Execution time	Memory
1280152		ducanh0811	Bitaro the Brave (JOI19_ho_t1)	C++20	100 / 100	216 ms	150404 KiB

joi2019_ho_t1

#include <bits/stdc++.h>
#define int long long
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define REV(i, a, b) for (int i = (a), _b = (b); i >= _b; --i)
using namespace std;

#define MAXN 3005
char a[MAXN][MAXN];
int prefO[MAXN][MAXN];
int prefI[MAXN][MAXN];
int n, m;

void solve() {
    cin >> n >> m;
    FOR(i, 1, n){
        FOR(j, 1, m){
            cin >> a[i][j];
        }
    }
    FOR(i, 1, n) {
        REV(j, m, 1){
            prefO[i][j] = prefO[i][j + 1];
            if (a[i][j] == 'O') prefO[i][j]++;
        }
    }
    REV(i, n, 1){
        FOR(j, 1, m){
            prefI[i][j] = prefI[i + 1][j];
            if (a[i][j] == 'I') prefI[i][j]++;
        }
    }
    int res = 0;
    FOR(i, 1, n){
        FOR(j, 1, m){
            if (a[i][j] == 'J'){
                res += (prefO[i][j] * prefI[i][j]);
            }
        }
    }
    cout << res;
}

int32_t main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);
    solve();
    return 0;
}

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