由于需要就地保存清零信息，所以把信息保存在第一行和第一列

 1 class Solution {
 2 public:
 3     void setZeroes(vector<vector<int> > &matrix) {
 4         const int ROW = matrix.size();
 5         if (ROW == 0)
 6             return;
 7         const int COL = matrix[0].size();
 8         if (COL == 0)
 9             return;
10         
11         // we store the 0 information in
12         // the 1st row and 1st col
13         bool R00 = false;
14         for(int i = 0; i < COL; ++i)
15             if (matrix[0][i] == 0)
16             {
17                 R00 = true;
18                 break;
19             }
20         bool C00 = false;
21         for(int i = 0; i < ROW; ++i)
22             if (matrix[i][0] == 0)
23             {
24                 C00 = true;
25                 break;
26             }
27         
28         // now traverse the remaining parts of
29         // the matrix and store 0 into the 
30         // first row
31         for(int i = 1; i < ROW; ++i)
32             for(int j = 1; j < COL; ++j)
33                 if (matrix[i][j] == 0)
34                 {
35                     matrix[i][0] = 0;
36                     matrix[0][j] = 0;
37                 }
38                 
39         // use the first row/col information to
40         // fill zeros
41         for(int i = 1; i < ROW; ++i)
42             if (matrix[i][0] == 0)
43                 for(int j = 1; j < COL; ++j)
44                     matrix[i][j] = 0;
45         
46         for(int i = 1; i < COL; ++i)
47             if (matrix[0][i] == 0)
48                 for(int j = 1; j < ROW; ++j)
49                     matrix[j][i] = 0;
50         
51         // Finally check the 1st row/col
52         if (R00)
53             fill(begin(matrix[0]), end(matrix[0]), 0);
54         if (C00)
55             for(int i = 0; i < ROW; ++i)
56                 matrix[i][0] = 0;
57         
58         return;
59     }
60 };