平衡二叉树

Question

使用后序遍历

import java.util.*;
public class Solution {
  private boolean isBalanced=true;
  public boolean IsBalanced_Solution(TreeNode root) {
    getDepth(root);
    return isBalanced;
  }
  public int getDepth(TreeNode root){
    if (!isBalanced){
      return -1;
    }
    if(root==null)
      return 0;
    int left=getDepth(root.left);
    int right=getDepth(root.right);
    if(Math.abs(left-right)>1){
      isBalanced=false;
    }
    return right>left ?right+1:left+1;
  }
}