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[Java教程][LeetCode] 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.

 

     这道题个人觉得不难,搞清楚平衡BTS的定义就好啦。

     还有就是boolean method最后不要想当然的想着反正写了>1就是false就想当然的return true,还是需要用method检查的哦。

public class Solution {      public boolean isBalanced(TreeNode root) {     if(root == null){       return true;     }     // situation that unbalanced     if(Math.abs(getHeight(root.left)-getHeight(root.right)) > 1){       return false;     }     // recur test balance     return isBalanced(root.left) && isBalanced(root.right);  }    // getHeight method   private int getHeight(TreeNode root){     if(root == null){       return 0;     }     //aviod 0 we can promise root wont be null but root.left and root.right could be null here    return 1+Math.max(getHeight(root.left), getHeight(root.right));   } }