站外题RE求救！！！悬棺（题目很水）

REEEEEE
题目传送门

#include <bits/stdc++.h>
#define int long long
using namespace std;
int fs[20][20];
int n,m;
void dfs(int x,int y,int k){
    if((x<=n)&&(x>=1)&&(y<=m)&&(y>=1)){
        fs[x][y]=k;
        dfs(x,y+1,k+1);
        dfs(x+1,y,k+1);
        dfs(x,y-1,k+1);
        dfs(x-1,y,k+1);
    }
}
signed main(){

    cin>>n>>m;
    dfs(1,1,1);
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            cout<<setw(3)<<fs[i][j];
        }
        cout<<endl;
    }
    return 0;
}