Submission #654647

#	Time	Username	Problem	Language	Result	Execution time	Memory
654647		horiseun	Collecting Mushrooms (NOI18_collectmushrooms)	C++11	100 / 100	28 ms	31400 KiB

mushrooms

#include <iostream>
#include <tuple>
#include <vector>
using namespace std;

#define f first
#define s second

int r, c, d, k, ans, spr, r1, r2, c1, c2;
vector<pair<int, int>> mushrooms;

int main() {

    ios_base::sync_with_stdio(false);
    cin.tie(0);

    cin >> r >> c >> d >> k;
    vector<vector<int>> grid(r + 5, vector<int> (c + 5, 0));
    vector<vector<int>> pref(r + 5, vector<int> (c + 5, 0));
    for (int i = 1; i <= r; i++) {
        for (int j = 1; j <= c; j++) {
            char x; cin >> x;
            if (x == 'M') {
                mushrooms.push_back({i, j});
            } else if (x == 'S') {
                grid[i][j] = 1;
            }
        }
    }

    for (int i = 1; i <= r; i++) {
        for (int j = 1; j <= c; j++) {
            pref[i][j] = pref[i - 1][j] + pref[i][j - 1] - pref[i - 1][j - 1] + grid[i][j];
        }
    }

    for (pair<int, int> p : mushrooms) {
        r1 = (p.f + d >= r ? r : p.f + d);
        c1 = (p.s + d >= c ? c : p.s + d);
        r2 = (p.f - d - 1 >= 0 ? p.f - d - 1 : 0);
        c2 = (p.s - d - 1 >= 0 ? p.s - d - 1 : 0); 
        spr = pref[r1][c1] - pref[r1][c2] - pref[r2][c1] + pref[r2][c2];
        if (spr >= k) ans++;
    }
    
    cout << ans << "\n";
    

}

• Subtask 1: 9 / 9
• Subtask 2: 10 / 10
• Subtask 3: 18 / 18
• Subtask 4: 23 / 23
• Subtask 5: 19 / 19
• Subtask 6: 21 / 21