Submission #853387

#	Time	Username	Problem	Language	Result	Execution time	Memory
853387		annabeth9680	Collecting Mushrooms (NOI18_collectmushrooms)	C++17	100 / 100	8 ms	3400 KiB

mushrooms

#include <bits/stdc++.h>
using namespace std;
const int MAXN = 5e5 + 11;
char grid[MAXN];
int dp[MAXN];
int main(){
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	int R,C,D,K; cin >> R >> C >> D >> K;
	for(int i = 0;i<R;++i){
        for(int j = 0;j<C;++j){
            cin >> grid[i*C+j];
            if(grid[i*C+j] == 'S'){
                int minr = max(i-D,0), maxr = min(i+D,R-1), minc = max(j-D,0), maxc = min(j+D,C-1);
                dp[minr*C+minc]++;
                if(maxr != R-1) dp[(maxr+1)*C+minc]--;
                if(maxc != C-1) dp[minr*C+maxc+1]--;
                if(maxr != R-1 && maxc != C-1) dp[(maxr+1)*C+maxc+1]++;
            }
        }
	}
	int ans = 0;
	for(int i = 0;i<R;++i){
        for(int j = 0;j<C;++j){
            if(i) dp[i*C+j] += dp[(i-1)*C+j];
            if(j) dp[i*C+j] += dp[i*C+j-1];
            if(i > 0 && j > 0) dp[i*C+j] -= dp[(i-1)*C+j-1];
            if(dp[i*C+j] >= K && grid[i*C+j] == 'M'){
                //cout << i << " " << j << "\n";
                ans++;
            }
        }
	}
	cout << ans << endl;
	return 0;
}

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