Eric 的小站

1
输入：matrix = [[1,2,3],[4,5,6],[7,8,9]]
2
输出：[1,2,3,6,9,8,7,4,5]

1
输入：matrix = [[1,2,3,4],[5,6,7,8],[9,10,11,12]]
2
输出：[1,2,3,4,8,12,11,10,9,5,6,7]

1
class Solution {
2
public:
3
    vector<int> spiralOrder(vector<vector<int>>& matrix) {
4
        int up = 0, down = matrix.size() - 1, left = 0,
5
            right = matrix[0].size() - 1;
6
        vector<int> result;
7
        while (left <= right && up <= down) {
8
            for (int i = left; i <= right; i++)
9
                result.push_back(matrix[up][i]);
10
            up++;
11
            for (int i = up; i <= down; i++)
12
                result.push_back(matrix[i][right]);
13
            right--;
14
            if (up <= down)
15
                for (int i = right; i >= left; i--)
16
                    result.push_back(matrix[down][i]);
17
            down--;
18
            if (left <= right)
19
                for (int i = down; i >= up; i--)
20
                    result.push_back(matrix[i][left]);
21
            left++;
22
        }
23
        return result;
24
    }
25
};