201412-2 Z字形扫描

#include <iostream>
using namespace std;
const int N = 510;
int g[N][N];
int main()
{
    int n;
    cin >> n;
    for (int i = 1; i <= n; i ++ ) 
        for (int j = 1; j <= n; j ++ ) 
            cin >> g[i][j];
    for (int i = 2; i <= 2 * n; i ++ )
        if (i % 2 == 0)
        {
            for (int j = i - 1; j; j -- )
                if (j >= 1 && j <= n && i - j >= 1 && i - j <= n)
                    cout << g[j][i - j] << ' ';
        }
        else 
        {
            for (int j = 1; j < i; j ++ )
                if (j >= 1 && j <= n && i - j >= 1 && i - j <= n)
                    cout << g[j][i - j] << ' ';
        }
    return 0;
}