代码如下

#include<iostream>
#include<string>
#include<stdio.h>
#include<stdlib.h>
using namespace std;
int n,a[30][30];
void to_do(){
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++)
            printf("%3d",a[i][j]);
        cout<<endl;
    }
    exit(1);
    return ;
}
void dfs(int h,int l,int now,string s){
    a[h][l]=now;
    if(now==n*n){
        to_do();
        return ;
    }
    now++;
    if(s=="right"){
        if(l==n||a[h][l+1]!=0) dfs(h+1,l,now,"down");
        else dfs(h,l+1,now,"right");
    }
    else if(s=="down"){
        if(h==n||a[h+1][l]!=0) dfs(h,l-1,now,"left");
        else dfs(h+1,l,now,"down");
    }
    else if(s=="left"){
        if(l==1||a[h][l-1]!=0) dfs(h-1,l,now,"up");
        else dfs(h,l-1,now,"left");
    }
    else{
        if(h==1||a[h-1][l]!=0) dfs(h,l+1,now,"right");
        else dfs(h-1,l,now,"up");
    } 
    return ; 
}
int main(){
    cin>>n;
    if(n==1){
        cout<<"  1";
        return 0;
    }
    dfs(1,1,1,"right");
    return 0;
}

为啥RE了4个点？