Submission #141281

#	Time	Username	Problem	Language	Result	Execution time	Memory
141281		meatrow	Collecting Mushrooms (NOI18_collectmushrooms)	C++17	100 / 100	40 ms	5112 KiB

mushrooms

//#pragma GCC optimize("O3")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,tune=native")
//#pragma GCC optimize ("unroll-loops")
#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using ld = long double;

vector<vector<int>> f;

void add(int x, int y) {
    for (int i = x; i < f.size(); i |= i + 1) {
        for (int j = y; j < f[0].size(); j |= j + 1) {
            f[i][j]++;
        }
    }
}

int get(int x, int y) {
    x = min(x, int(f.size()) - 1);
    y = min(y, int(f[0].size()) - 1);
    int res = 0;
    for (int i = x; i >= 0; i = (i & (i + 1)) - 1) {
        for (int j = y; j >= 0; j = (j & (j + 1)) - 1) {
            res += f[i][j];
        }
    }
    return res;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    int r, c, d, k;
    cin >> r >> c >> d >> k;
    vector<vector<char>> field(r, vector<char>(c));
    f.assign(r, vector<int>(c, 0));
    for (int i = 0; i < r; i++) {
        for (int j = 0; j < c; j++) {
            cin >> field[i][j];
            if (field[i][j] == 'S') {
                add(i, j);
            } 
        }
    }
    int ans = 0;
    for (int i = 0; i < r; i++) {
        for (int j = 0; j < c; j++) {
            if (field[i][j] == 'M') {
                int cnt = get(i + d, j + d) - get(i + d, j - d - 1)
                - get(i - d - 1, j + d) + get(i - d - 1, j - d - 1);
                if (cnt >= k) {
                    ans++;
                }
            }
        }
    }
    cout << ans;
    return 0;
}

Compilation message (stderr)

mushrooms.cpp: In function 'void add(int, int)':
mushrooms.cpp:14:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = x; i < f.size(); i |= i + 1) {
                     ~~^~~~~~~~~~
mushrooms.cpp:15:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int j = y; j < f[0].size(); j |= j + 1) {
                         ~~^~~~~~~~~~~~~

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