Submission #877887

#	Time	Username	Problem	Language	Result	Execution time	Memory
877887		konber	T-Covering (eJOI19_covering)	C++14	30 / 100	60 ms	12124 KiB

covering

#include <iostream>
#include <vector>

using namespace std;

vector<vector<int>> a, grid;
vector<pair<int, int>> sp;
int K, N, M;

int f(int x){
    if(x==K) return 0;
    int i=sp[x].first, j=sp[x].second;
    int s1=-1, s2=-1, s3=-1, s4=-1;
    if(i-1>=0 && i+1<M && j-1>=0){
        if(grid[i][j]+grid[i-1][j]+grid[i+1][j]+grid[i][j-1]==0){
            grid[i][j]=grid[i-1][j]=grid[i+1][j]=grid[i][j-1]=1;
            int d=f(x+1);
            if(d!=-1) s1 = a[i][j]+a[i-1][j]+a[i+1][j]+a[i][j-1]+d;
            grid[i][j]=grid[i-1][j]=grid[i+1][j]=grid[i][j-1]=0;
        }
    }
    if(i-1>=0 && i+1<M && j+1<N){
        if(grid[i][j]+grid[i-1][j]+grid[i+1][j]+grid[i][j+1]==0){
            grid[i][j]=grid[i-1][j]=grid[i+1][j]=grid[i][j+1]=1;
            int d=f(x+1);
            if(d!=-1) s2 = a[i][j]+a[i-1][j]+a[i+1][j]+a[i][j+1]+d;
            grid[i][j]=grid[i-1][j]=grid[i+1][j]=grid[i][j+1]=0;
        }
    }
    if(j-1>=0 && j+1<N && i+1<M){
        if(grid[i][j]+grid[i][j-1]+grid[i][j+1]+grid[i+1][j]==0){
            grid[i][j]=grid[i][j-1]=grid[i][j+1]=grid[i+1][j]=1;
            int d=f(x+1);
            if(d!=-1) s3 = a[i][j]+a[i][j-1]+a[i][j+1]+a[i+1][j]+d;
            grid[i][j]=grid[i][j-1]=grid[i][j+1]=grid[i+1][j]=0;
        }
    }
    if(j-1>=0 && j+1<N && i-1>=0){
        if(grid[i][j]+grid[i][j-1]+grid[i][j+1]+grid[i-1][j]==0){
            grid[i][j]=grid[i][j-1]=grid[i][j+1]=grid[i-1][j]=1;
            int d=f(x+1);
            if(d!=-1) s4 = a[i][j]+a[i][j-1]+a[i][j+1]+a[i-1][j]+d;
            grid[i][j]=grid[i][j-1]=grid[i][j+1]=grid[i-1][j]=0;
        }
    }
    return max(s1, max(s2, max(s3, s4)));
}

int main()
{
    scanf("%d%d", &M, &N);
    a.resize(M, vector<int>(N));
    grid.resize(M, vector<int>(N));
    for(int i=0; i < M; i++){
        for(int j=0; j < N; j++)
            scanf("%d", &a[i][j]);
    }
    scanf("%d", &K);
    sp.resize(K);
    for(int i=0; i < K; i++){
        scanf("%d%d", &sp[i].first, &sp[i].second);
    }
    if(K <= 10){
        int ans=f(0);
        if(ans>=0) printf("%d\n", ans);
        else printf("No\n");
    }
    else{
        for(int i=0; i < K; i++){
            grid[sp[i].first][sp[i].second] = 1;
        }
        int sum=0;
        bool valid=true;
        for(int x=0; x < K; x++){
            int i=sp[x].first, j=sp[x].second;
            int s1=-1, s2=-1, s3=-1, s4=-1;
            if(i-1>=0 && i+1<M && j-1>=0 && grid[i-1][j]+grid[i+1][j]+grid[i][j-1]==0)
                s1=a[i][j]+a[i-1][j]+a[i+1][j]+a[i][j-1];
            if(i-1>=0 && i+1<M && j+1<N && grid[i-1][j]+grid[i+1][j]+grid[i][j+1]==0)
                s2=a[i][j]+a[i-1][j]+a[i+1][j]+a[i][j+1];
            if(j-1>=0 && j+1<N && i-1>=0 && grid[i][j-1]+grid[i][j+1]+grid[i-1][j]==0)
                s3=a[i][j]+a[i][j-1]+a[i][j+1]+a[i-1][j];
            if(j-1>=0 && j+1<N && i+1<M && grid[i][j-1]+grid[i][j+1]+grid[i+1][j]==0)
                s4=a[i][j]+a[i][j-1]+a[i][j+1]+a[i+1][j];
            int d=max(s1, max(s2, max(s3, s4)));
            if(d==-1){
                valid=false;
                break;
            }
            sum += d;
        }
        if(!valid) printf("No\n");
        else printf("%d\n", sum);
    }
}

Compilation message (stderr)

covering.cpp: In function 'int main()':
covering.cpp:51:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   51 |     scanf("%d%d", &M, &N);
      |     ~~~~~^~~~~~~~~~~~~~~~
covering.cpp:56:18: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   56 |             scanf("%d", &a[i][j]);
      |             ~~~~~^~~~~~~~~~~~~~~~
covering.cpp:58:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   58 |     scanf("%d", &K);
      |     ~~~~~^~~~~~~~~~
covering.cpp:61:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   61 |         scanf("%d%d", &sp[i].first, &sp[i].second);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 0 / 10
• Subtask 4: 0 / 10
• Subtask 5: 15 / 15
• Subtask 6: 0 / 20
• Subtask 7: 0 / 30