二维数组的遍历

读入数据，接着对其进行多个方向遍历即可。

#include <bits/stdc++.h>
using namespace std;

const int N = 1001;
int g[N][N];

int main()
{
    int n, m;
    cin >> n >> m;
    int t = 0;
    for(int i = 1; i <= n; i ++)
        for(int j = 1; j <= m; j ++)
            g[i][j] = ++ t;
    
    int r = 1, c = 1;
    cout << g[r][c];
    g[r][c] = 0;
    for(int i = 2; i <= n * m; i ++)
    {
        while(r + 1 <= n && g[r + 1][c])
        {
            cout << "," << g[++ r][c];
            g[r][c] = 0;
        }
        while(c + 1 <= m && g[r][c + 1])
        {
            cout << ","  << g[r][++ c];
            g[r][c] = 0;
        }
        while(r - 1 >= 1 && g[r - 1][c])
        {
            cout << "," << g[-- r][c];
            g[r][c] = 0;
        }
        while(c - 1 >= 1 && g[r][c - 1])
        {
            cout << "," << g[r][-- c];
            g[r][c] = 0;
        }
    }
    return 0;
}