Give a N*N matrix, print it out diagonally.

Follow up, if it is a M*N matrix, how to print it out.

Example: 

print: 

 // http://www.careercup.com/question?id=5661939564806144

 #include <cstdio>

 #include <vector>

 using namespace std;

 class Solution {

 public:

     void printDiagonal(vector<vector<int> > &matrix) {

         int n, m;

         n = (int)matrix.size();

         if (n == ) {

             return;

         }

         m = (int)matrix[].size();

         if (m == ) {

             return;

         }

         int i, j;

         bool first;

         for (i = ; i < n + m; ++i) {

             first = true;

             for (j = (i < m ? i : m - ); j >= ; --j) {

                 if (i - j <  || i - j > n - ) {

                     break;

                 }

                 printf((first ? "%d" : " %d"), matrix[i - j][j]);

                 first = false;

             }

             printf("\n");

         }

     };

 };