LeetCode_OJ【54】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]

.

这道题思路很简单，但是有些边边角角要注意，特别要注意m>n和m<n时里层的循环。

public class Solution {
public List<Integer> spiralOrder(int[][] matrix) {
List<Integer> list = new ArrayList<Integer>();
if(matrix.length == 0)
return list;
for(int i = 0 ; i < (matrix.length+1) /2 && i < (matrix[0].length+1)/2 ; i++){
int flagX = 0;
int flagY = 0;
for(int j = i,count =0 ; j < matrix[i].length - i ; j ++){
list.add(matrix[i][j]);
count ++;
if(count ==2)
flagX = 1;
}
for(int j = i +1 ; j < matrix.length - i ; j ++){
list.add(matrix[j][matrix[i].length -1 -i]);
flagY = 1;
}
if(flagY > 0){
for(int j = matrix[i].length -i -2; j >= i ; j --)
list.add(matrix[matrix.length -1 -i][j]);
}
if(flagX > 0){
for(int j = matrix.length -2 -i; j > i ; j--)
list.add(matrix[j][i]);
}
}
return list;
}
}