Solution.cpp

class Solution {
public:
    vector<int> spiralOrder(vector<vector<int>>& matrix) {
        int m = matrix.size(), n = matrix[0].size();
        int dirs[5] = {0, 1, 0, -1, 0};
        int i = 0, j = 0, k = 0;
        vector<int> ans;
        bool vis[m][n];
        memset(vis, false, sizeof(vis));
        for (int h = m * n; h; --h) {
            ans.push_back(matrix[i][j]);
            vis[i][j] = true;
            int x = i + dirs[k], y = j + dirs[k + 1];
            if (x < 0 || x >= m || y < 0 || y >= n || vis[x][y]) {
                k = (k + 1) % 4;
            }
            i += dirs[k];
            j += dirs[k + 1];
        }
        return ans;
    }
};