0分求助

P1162 填涂颜色

Sci_8633 @ 2024-07-13 17:33:25

经检验,问题出在bfs()函数中。

#include<bits/stdc++.h>
using namespace std;
int n;
int dx[4]={0,0,-1,1};
int dy[4]={1,-1,0,0};
int vis[35][35];
char s[35][35];
struct node{
    int x;
    int y;
};
queue<node>q;
void bfs(int x,int y){
    q.push({x,y});
    while(!q.empty()){
        node a=q.front();
        q.pop();
        for(int i=0;i<4;++i){
            int nx=a.x+dx[i];
            int ny=a.y=dy[i];
            if(nx>=1&&nx<=n&&ny>=1&&ny<=n&&vis[nx][ny]==0&&s[nx][ny]=='0'){
                vis[nx][ny]=1;
                s[nx][ny]='2';
                q.push({nx,ny});
            }
        }
    }
}
int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin>>n;
    for(int i=1;i<=n;++i)
        for(int j=1;j<=n;++j)
            cin>>s[i][j];
    for(int i=1;i<=n;++i)
        for(int j=1;j<=n;++j)
            if(i==1&&s[i][j]=='0'||i==n&&s[i][j]=='0'||j==1&&s[i][j]=='0'||j==n&&s[i][j]=='0') /*靠边的‘0’未被包裹*/
                vis[i][j]=-1;
    for(int i=1;i<=n;++i)
        for(int j=1;j<=n;++j)
            if(vis[i][j]!=-1){
                vis[i][j]=1;
                bfs(i,j);
                break;
            }
    for(int i=1;i<=n;++i,cout<<'\n')
        for(int j=1;j<=n;++j)
            if(vis[i][j]==-1){
                s[i][j]='0';
                cout<<s[i][j]<<' ';
            }else   cout<<s[i][j]<<' ';
    return 0;
}

by Sci_8633 @ 2024-07-13 17:34:13

输出时1字框中的2都是0


by wby_1234 @ 2024-07-13 17:56:58

题号说一下,Please


by wuzhitong @ 2024-07-18 18:52:07

dfs的AC代码可以参考一下:

#include<bits/stdc++.h>
using namespace std;
int dx[4]={0,0,1,-1},dy[4]={1,-1,0,0},n,s;
int a[31][31];
void dfs(int x,int y)
{
    if(x<1||y<1||x>n||y>n||a[x][y]!=0)return;
    a[x][y]=3;
    for(int i=0;i<4;i++)dfs(x+dx[i],y+dy[i]);
}
int main()
{
    cin>>n;
    for(int i=1;i<=n;i++)for(int j=1;j<=n;j++)cin>>a[i][j];
    for(int i=1;i<=n;i++)dfs(1,i);
    for(int i=1;i<=n;i++)dfs(i,n);
    for(int i=1;i<=n;i++)dfs(i,1);
    for(int i=1;i<=n;i++)dfs(n,i);
    for(int i=1;i<=n;i++)
    {
       for(int j=1;j<=n;j++)
       {
          if(a[i][j]==3)cout<<"0 ";
          if(a[i][j]==1)cout<<"1 ";
          if(a[i][j]==0)cout<<"2 ";
       }
       cout<<"\n";
    }
    return 0;
}

(求关 QWQ


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