leetcode54 Spiral Matrix

Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order.

For example,
Given the following matrix:

[
 [ 1, 2, 3 ],
 [ 4, 5, 6 ],
 [ 7, 8, 9 ]
]

You should return [1,2,3,6,9,8,7,4,5].

 1 class Solution {
 2 public:
 3     vector<int> spiralOrder(vector<vector<int>>& matrix) {
 4         vector<int> ans;
 5         int xmin=0,ymin=0;
 6         int xmax=matrix.size();
 7         if(!xmax)
 8             return ans;
 9         int ymax=matrix[0].size();
10         
11         int dir=1;
12         int count=0;
13         int cmax=xmax*ymax;
14         xmax--;
15         ymax--;
16         
17         int x=0,y=0;
18         ans.push_back(matrix[x][y]);
19         count++;
20     
21         while(count<cmax)
22         {
23             if(dir==1)
24             {
25                 if(y+1>ymax)
26                 {
27                     dir=2;
28                     xmin++;
29                 }
30                 else
31                 {
32                     y++;
33                     ans.push_back(matrix[x][y]);
34                     count++;
35                 }
36             }
37             else if(dir==2)
38             {
39                 if(x+1>xmax)
40                 {
41                     dir=3;
42                     ymax--;
43                 }
44                 else
45                 {
46                     x++;
47                     ans.push_back(matrix[x][y]);
48                     count++;
49                 }
50             }
51             else if(dir==3)
52             {
53                 if(y-1<ymin)
54                 {
55                     dir=4;
56                     xmax--;
57                 }
58                 else
59                 {
60                     y--;
61                     ans.push_back(matrix[x][y]);
62                     count++;
63                 }
64             }
65             else
66             {
67                 if(x-1<xmin)
68                 {
69                     dir=1;
70                     ymin++;
71                 }
72                 else
73                 {
74                     x--;
75                     ans.push_back(matrix[x][y]);
76                     count++;
77                 }
78             }
79         }
80         return ans;
81     }
82 };

View Code