题解出场

#include<bits/stdc++.h>
using namespace std;
int n,x,y=-1;
const int N=1e3+1;
int a[1001][1001];
int main(){
	cin>>n;
	int cnt=1;
	while(cnt<=n*n){
		while(y+1<n and a[x][y+1]==0){
			a[x][++y]=cnt++;
		}
		while(x+1<n and a[x+1][y]==0){
			a[++x][y]=cnt++;
		}
		while(y-1>=0 and a[x][y-1]==0){
			a[x][--y]=cnt++;
		}
		while(x-1>=0 and a[x-1][y]==0){
			a[--x][y]=cnt++;
		}
	}
	for(int i=0;i<n;i++){
		for(int j=0;j<n;j++){
			cout<<a[i][j]<<" ";
		}
		cout<<endl;
	}
	return 0;
}