Steward

分享是一種喜悅、更是一種幸福

程式語言 - LeetCode - C++ - 498. Diagonal Traverse

---

題目：


解答：

class Solution {
public:
    vector<int> findDiagonalOrder(vector<vector<int>>& mat) {
        int m = mat.size();
        int n = mat[0].size();
        unordered_map<int, vector<int>> mp;
        vector<int> ans;

        for (int i = 0; i < m; ++i) {
            for (int j = 0; j < n; ++j) {
                mp[i + j].push_back(mat[i][j]);
            }
        }
        
        for (int i = 0; i < m + n - 1; ++i) {
            auto &v = mp[i];

            if (i % 2 == 0) {
                reverse(v.begin(), v.end());
            }

            ans.insert(ans.end(), v.begin(), v.end());
        }

        return ans;
    }
};