LeetCode Spiral Matrix 细节&数组

思想：

一步一步进行判断，从左往右，从上到下，从右往左，从下到上。

class Solution {
public:
    vector<int> spiralOrder(vector<vector<int> > &matrix) {
        vector<int> res;
        if(matrix.empty()) return res;
        int beginX = 0, endX = matrix[0].size() - 1;
        int beginY = 0, endY = matrix.size() - 1;
        while(true) {
            //from left to right
            for(int j = beginX; j <= endX; j++) {
                res.push_back(matrix[beginY][j]);
            }
            if(++beginY > endY) break;
            //from top to bottom
            for(int i = beginY; i <= endY; i++) {
                res.push_back(matrix[i][endX]);
            }
            if(beginX > --endX) break;
            //from right to left
            for(int j = endX; j >= beginX; j--) {
                res.push_back(matrix[endY][j]);
            }
            if(beginY > --endY) break;
            //from bottom to top
            for(int i = endY; i >= beginY; i--) {
                res.push_back(matrix[i][beginX]);
            }
            if(++beginX > endX) break;
        }
        return res;
    }
};