Submission #1174706

#	Time	Username	Problem	Language	Result	Execution time	Memory
1174706		Ciprian	Collecting Mushrooms (NOI18_collectmushrooms)	C++20	100 / 100	190 ms	198844 KiB

mushrooms

#include <bits/stdc++.h>
using namespace std;
#define int long long 
int d1[4]={0,0,1,-1};
int d2[4]={1,-1,0,0};
int32_t main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n,m,d,k;
    cin>>n>>m>>d>>k;
    map<pair<int,int>, int>wet;
    vector<pair<int,int>>sprinkler, mush;
    for(int i=1; i<=n; i++){
        for(int j=1; j<=m; j++){
            char x;
            cin>>x;
            if(x=='S')sprinkler.push_back({i,j});
            if(x=='M')mush.push_back({i,j});
        }
    }if(min(n, m)<=500){
        if(n<m){
            vector<pair<int,int>>intervals[n+2];
            
            for(auto e:sprinkler){
                for(int i=max(e.first-d, 1LL); i<=min(e.first+d,n); i++){
                    intervals[i].push_back({max(e.second-d, 1LL), min(e.second+d, m)});
                }
                
                
            }//sort(intervals.begin(), intervals.end());
            int cnt=0;
            vector<vector<int>>p(n+2,vector<int>(m+2, 0)), pref(n+2,vector<int>(m+2, 0));
            for(int i=1; i<=n; i++){
                for(auto e: intervals[i]){
                    p[i][e.first]++;
                    p[i][e.second+1]--;
                }
            }for(int i=1; i<=n; i++){
                for(int j=1; j<=m; j++){
                    pref[i][j]=pref[i][j-1]+p[i][j];
                }
            }for(auto e: mush){
                if(pref[e.first][e.second]>=k)cnt++;
            }cout<<cnt<<endl;
        }else{
            vector<pair<int,int>>intervals[m+2];
            
            for(auto e:sprinkler){
                for(int i=max(e.second-d, 1LL); i<=min(e.second+d,m); i++){
                    intervals[i].push_back({max(e.first-d, 1LL), min(e.first+d, n)});
                }
                
                
            }//sort(intervals.begin(), intervals.end());
            int cnt=0;
            vector<vector<int>>p(m+2,vector<int>(n+2, 0)), pref(m+2,vector<int>(n+2, 0));
            for(int i=1; i<=m; i++){
                for(auto e: intervals[i]){
                    p[i][e.first]++;
                    p[i][e.second+1]--;
                }
            }for(int i=1; i<=m; i++){
                for(int j=1; j<=n; j++){
                    pref[i][j]=pref[i][j-1]+p[i][j];
                }
            }for(auto e: mush){
                if(pref[e.second][e.first]>=k)cnt++;
            }cout<<cnt<<endl;
        }
        
    }else {
        for(auto e: mush){
            for(auto f: sprinkler){
                if(max(abs(e.first-f.first), abs(e.second-f.second))<=d){
                    wet[e]++;
                }
            }
        }
        int cnt=0;
        for(auto e: mush){
            //cout<<wet[e.first][e.second]<<endl;
            if(wet[e]>=k)cnt++;
        }cout<<cnt<<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