Leetcode 832 Solution

This article provides solution to leetcode question 832 (binary-tree-pruning)

https://leetcode.com/problems/binary-tree-pruning

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 {
public:
    bool _pruneTree(TreeNode* root) {
        if (root == NULL)
            return true;

        if (!_pruneTree(root->left))
            root->left = NULL;

        if (!_pruneTree(root->right))
            root->right = NULL;

        if (root->val == 0 && !root->left && !root->right)
            return false;

        return true;
    }

    TreeNode* pruneTree(TreeNode* root) {
        return _pruneTree(root) ? root : NULL;
    }
};