Submission #862441

#	Time	Username	Problem	Language	Result	Execution time	Memory
862441		Irate	Collecting Mushrooms (NOI18_collectmushrooms)	C++14	100 / 100	39 ms	33136 KiB

mushrooms

#include<bits/stdc++.h>
using namespace std;
struct Fenwick{
    vector<int>BIT;
    int sz;
    void Update(int pos, int val){
        while(pos <= sz){
            BIT[pos] += val;
            pos += (pos & -pos);
        }
    }
    int Query(int pos){
        int sum = 0;
        while(pos > 0){
            sum += BIT[pos];
            pos -= (pos & -pos);
        }
        return sum;
    }
};  
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n, m, d, k;
    cin >> n >> m >> d >> k;
    vector<vector<char>>grid(n + 1, vector<char>(m + 1));
    Fenwick tree[m + 1];
    for(int i = 0;i <= m;++i){
        tree[i].BIT.resize(n + 1);
        tree[i].sz = n;
    }
    for(int i = 1;i <= n;++i){
        for(int j = 1;j <= m;++j){
            cin >> grid[i][j];
            if(grid[i][j] == 'S'){
                int x = max(i - d, 1);
                int y = max(j - d, 1);
                int x_end = min(i + d, n);
                int y_end = min(j + d, m);
                tree[y].Update(x, 1);
                if(x_end + 1 <= n)tree[y].Update(x_end + 1, -1);
                if(y_end + 1 <= m){
                    tree[y_end + 1].Update(x, -1);
                    if(x_end + 1 <= n)tree[y_end + 1].Update(x_end + 1, 1);
                }
            }
        }
    }
    int res = 0;
    for(int i = 1;i <= n;++i){
        int sum = 0;
        for(int j = 1;j <= m;++j){
            sum += tree[j].Query(i);
            if(grid[i][j] == 'M' && sum >= k){
                res++;
            }
        }
    }
    cout << res;
}

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