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Balanced Binary Tree.cpp
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Balanced Binary Tree.cpp
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#include <iostream>
struct TreeNode {
int val;
TreeNode *left;
TreeNode *right;
TreeNode() : val(0), left(nullptr), right(nullptr) {}
TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
TreeNode(int x, TreeNode *left, TreeNode *right)
: val(x), left(left), right(right) {}
};
class Solution {
public:
bool isBalanced(TreeNode *root) {
std::pair<int, bool> pair = helper(root);
return pair.second;
}
private:
std::pair<int, bool> helper(TreeNode *root) {
if (!root) {
return {0, true};
}
std::pair<int, int> leftPair = helper(root->left);
int leftHeight = leftPair.first;
int leftBalanced = leftPair.second;
if (!leftBalanced) {
return {-1, false};
}
std::pair<int, int> rightPair = helper(root->right);
int rightHeight = rightPair.first;
int rightBalanced = rightPair.second;
if (!rightBalanced) {
return {-1, false};
}
if (abs(rightHeight - leftHeight) > 1) {
return {-1, false};
}
return {1 + std::max(leftHeight, rightHeight), true};
}
};