题解 | 螺旋矩阵

#include <algorithm>
#include <vector>
class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param matrix int整型vector<vector<>> 
     * @return int整型vector
     */
    vector<int> spiralOrder(vector<vector<int> >& matrix) {
        // write code here
        vector<int> ans;
        int m = matrix.size();
        if (!m) return ans;
        int n = matrix[0].size();

        vector<vector<bool>> st(m, vector<bool> (n));
        int dx[4] = {0, 1, 0, -1}, dy[4] = {1, 0, -1, 0};

        for (int i = 0, x = 0, y = 0, d = 0; i < m * n; i++) {
            ans.push_back(matrix[x][y]);
            st[x][y] = true;

            int a = x + dx[d], b = y + dy[d];
            if (a < 0 || a >= m || b < 0 || b >= n || st[a][b]) {
                d = (d + 1) % 4;
                a = x + dx[d], b = y + dy[d];
            }

            x = a, y = b;
        }
        return ans;
    }
};