经典蛇形矩阵 洛谷 P5731

#include<iostream>
#include<cmath>
using namespace std;

const int N = 11;
int f[N][N];

int main()
{
    int n;
    cin >> n;
    
    int dx[4] = {0, 1, 0, -1}, dy[4] = {1, 0, -1, 0};
    int x = 1, y = 1,d = 0;
    for (int i = 1;i <= n * n;i ++)
    {
        f[x][y] = i;
        int a = x + dx[d];
        int b = y + dy[d];
        if (a > n || a < 1 || b > n || b < 1 || f[a][b])
        {
            d = (d + 1) % 4;
            a = x + dx[d];
            b = y + dy[d];
        }
        x = a;
        y = b;
    }
    
    for (int i = 1;i <= n;i ++)
    {
        for (int j = 1;j <= n;j ++)
            printf("%3d",f[i][j]);
        cout << endl;
    }
    
    return 0;
}

 

https://www.luogu.com.cn/problem/P5731