Leetcode 366 Solution

This article provides solution to leetcode question 366 (find-leaves-of-binary-tree)
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https://leetcode.com/problems/find-leaves-of-binary-tree

Solution

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
    map<int, vector<int>> a;
public:
    int doFindLeaves(TreeNode* root)
    {
        if (root == NULL)
            return 0;

        int left_depth = doFindLeaves(root->left);
        int right_depth = doFindLeaves(root->right);

        int depth = max(left_depth, right_depth);
        a[depth].push_back(root->val);
        return depth + 1;
    }

    vector<vector<int>> findLeaves(TreeNode* root) {
        doFindLeaves(root);

        vector<vector<int>> res;
        for (auto pair : a)
            res.push_back(pair.second);
        return res;
    }
};