Submission #765534

#	Time	Username	Problem	Language	Result	Execution time	Memory
765534		NK_	Bitaro the Brave (JOI19_ho_t1)	C++17	100 / 100	82 ms	80740 KiB

joi2019_ho_t1

// Success consists of going from failure to failure without loss of enthusiasm
#include <bits/stdc++.h>

using namespace std;

#define nl '\n'

template<class T> using V = vector<T>;
using str = string;
using ll = long long;

int main() {
	cin.tie(0)->sync_with_stdio(0);
	
	int N, M; cin >> N >> M;
	V<str> A(N); for(auto& x : A) cin >> x;

	V<V<int>> I(N, V<int>(M, 0)), O(N, V<int>(M, 0));

	ll ans = 0;
	for(int i = N - 1; i >= 0; i--) for(int j = M - 1; j >= 0; j--) {
		I[i][j] = (A[i][j] == 'I');
		if (i+1 < N) I[i][j] += I[i+1][j];

		O[i][j] = (A[i][j] == 'O');
		if (j+1 < M) O[i][j] += O[i][j+1];

		if (A[i][j] == 'J') ans += O[i][j] * 1LL * I[i][j];
	}

	cout << ans << nl;

    return 0;
}

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