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BalancedBinaryTree.hpp
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/
BalancedBinaryTree.hpp
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//Balanced Binary Tree
//
//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 "Tree.hpp"
#include <cmath>
/**
* Definition for binary tree
* 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 (NULL == root)
return true;
if (NULL == root->left && NULL != root->right)
return (maxDepth(root->right) <= 1);
else if (NULL != root->left && NULL == root->right)
return (maxDepth(root->left) <= 1);
else if (NULL == root->left && NULL == root->right)
return true;
else return (isBalanced(root->left) &&
isBalanced(root->right) &&
std::abs(maxDepth(root->left) - maxDepth(root->right)) <= 1);
}
int maxDepth(TreeNode *root) {
if (NULL == root)
return 0;
if (NULL == root->left &&
NULL == root->right)
return 1;
int lhs = maxDepth(root->left);
int rhs = maxDepth(root->right);
return (lhs > rhs) ? lhs + 1 : rhs + 1;
}
};