题解 | #顺时针打印矩阵# 11-1 03 画图

class Solution {
public:
    vector<int> printMatrix(vector<vector<int> > matrix) {
        
        int high = matrix.size() - 1;
        int right = matrix[0].size() - 1;
        int low = 0, left = 0;
        vector<int>ret;
        
        if(matrix.size() == 0) {
            return ret;
        }
        while (low <= high && left <= right) {
            // 向右的话，竖直反向是不变的，low++
            for(int i = left; i <= right; i++) {
                ret.push_back(matrix[low][i]);
            }
            // 向下，列不变的
            for(int i = low + 1; i <= high; i++) {
                ret.push_back(matrix[i][right]);
            }
            // 向左
            if (low < high) {
                for (int i = right - 1; i >= left; i--) {
                    ret.push_back(matrix[high][i]);
                }
            }
            // 向上，为了避免重复访问
            if (left < right) {
                for (int i = high - 1; i >= low + 1; i--) {
                    ret.push_back(matrix[i][left]);
                }
            }
            low ++;
            high--;
            left++;
            right--;
        }
        
        return ret;
    }
};