题目:
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]
.
class Solution {
public:
vector<int> spiralOrder(vector<vector<int> > &matrix) {
if (matrix.size() == 0)
return vector<int>();
vector<int> ans;
int m = matrix.size();
int n = matrix[0].size();
int x1 = 0, y1 = 0, x2 = m - 1, y2 = n - 1;
while (x1 <= x2 && y1 <= y2) {
for (int j = y1; j <= y2; j++)
ans.push_back(matrix[x1][j]);
for (int i = x1 + 1; i <= x2; i++)
ans.push_back(matrix[i][y2]);
if (x1 != x2) {
for (int j = y2 - 1; j >= y1; j--)
ans.push_back(matrix[x2][j]);
}
if (y1 != y2) {
for (int i = x2 - 1; i >= x1 + 1; i--)
ans.push_back(matrix[i][y1]);
}
x1++, y1++, x2--, y2--;
}
return ans;
}
};