LeetCode:110. 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.

1.思路：计算深度 左右子数平衡 并且判断深度差值的绝对值小于等于1 return true！

<span style="font-size:18px;">public int depth(TreeNode root) {
if (root == null) {
return 0;
} else{
int a = depth(root.left);
int b = depth(root.right);
return a>b ? a+1:b+1;
}
}
public boolean isBalanced(TreeNode root) {
if(root == null) { return true; }
if(root.left == null && root.right == null) {return true;}
int leftLength = depth(root.left);
int rightLength = depth(root.right);
if(Math.abs(leftLength - rightLength) > 1) {
return false;
}else {
return isBalanced(root.left) && isBalanced(root.right);
}
}</span>