1. 给一个二维数组，对角线打印 例子： 1 2 3 4.5 6 7 8 9 10 11 12 打印出 1 2 5 3 6 9 4 7 10 8 11 12

.cpp

// http://www.1point3acres.com/bbs/forum.php?mod=viewthread&tid=141288&extra=page%3D1%26filter%3Dsortid%26sortid%3D311%26sortid%3D311
#include <iostream>
#include <vector>
#include <algorithm>
#include <unordered_map>
#include <string>
using namespace std;

void print(vector<vector<int>> a) {
    int m = (int)a.size();
    if (m == 0)	return;
    int n = (int)a[0].size();
    if (n == 0)	return;
    int square = min(m, n);
    // phase 1
    for (int i = 0; i < square; i++) {
        for (int j = i; j >= 0; j--) {
            cout << a[i-j][j] << " ";
        }
        cout << endl;
    }
    if (m >= n) {
        // phase 2
        for (int i = square; i < m; i++) {
            for (int j = 0; j < square; j++) {
                cout << a[i-j][j] << " ";
            }
            cout << endl;
        }
        // phase 3
        for (int i = square - 1; i > 0; i--) {
            for (int j = 0; j < i; j++) {
                cout << a[m-i+j][n-1-j] << " ";
            }
            cout << endl;
        }
    }
}

int main() {
    vector<vector<int>> v = {{1,2,3},{4,5,6},{7,8,9},{10,11,12}};
    print(v);
    return 0;
}