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balanced_binary_tree.cpp
46 lines (40 loc) · 1.31 KB
/
balanced_binary_tree.cpp
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/* Given a binary tree, determine if it is height-balanced.
* For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ by more than 1. */
#include <iostream>
#include <vector>
#include <stdlib.h>
using namespace std;
struct TreeNode {
int val;
TreeNode* left;
TreeNode* right;
TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};
class Solution {
public:
bool isBalanced(TreeNode* root) {
if (root == NULL) return true;
bool result = true;
isBalancedAux(root, result);
return result;
}
private:
// isBalancedAux return the height of tree
// and check balanced or not at the same time
int isBalancedAux(TreeNode* root, bool& is_balanced) {
if (root == NULL) return 0;
int left_height = isBalancedAux(root->left, is_balanced);
int right_height = isBalancedAux(root->right, is_balanced);
if (is_balanced)
is_balanced = abs(left_height - right_height) <= 1;
return max(left_height, right_height) + 1;
}
};
int main() {
Solution sol;
TreeNode* root = new TreeNode(1);
root->right = new TreeNode(2);
root->right->left = new TreeNode(3);
if (!sol.isBalanced(root)) cout << "pass test 1";
cout << endl;
}