題見洛谷
#include<iostream>#include<cstdio>#include<algorithm>#include<cstring>#include<string>#include<cmath>#include<vector>using namespace std;int a[40][40],n;bool f[40][40];int dx[]={0,1,-1,0,0};int dy[]={0,0,0,1,-1};struct que{ int x; int y;}pos[2000];void bfs(){ int head=0,tail=0; for(int i=1;i<=n;i++){ if(a[1][i]==0&&!f[1][i]){ pos[++tail].x=1;pos[tail].y=i;f[1][i]=true; } if(a[i][1]==0&&!f[i][1]){ pos[++tail].x=i;pos[tail].y=1;f[i][1]=true; } if(a[n][i]==0&&!f[n][i]){ pos[++tail].x=n;pos[tail].y=i;f[n][i]=true; } if(a[i][n]==0&&!f[i][n]){ pos[++tail].x=i;pos[tail].y=n;f[i][n]=true; } while(head<tail){ head++; for(int i=1;i<=4;i++){ int nx=pos[head].x+dx[i],ny=pos[head].y+dy[i]; if(nx<=n&&nx>=1&&ny>=1&&ny<=n) if(!f[nx][ny]){ pos[++tail].x=nx;pos[tail].y=ny;f[nx][ny]=true; } } } }}int main(){ scanf("%d",&n); for(int i=1;i<=n;i++) for(int j=1;j<=n;j++){ scanf("%d",&a[i][j]); if(a[i][j]==1)f[i][j]=true; } bfs(); for(int i=1;i<=n;i++){ for(int j=1;j<=n;j++) if(!f[i][j])新聞熱點
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