zoukankan      html  css  js  c++  java
  • [Algorithm] 617. Merge Two Binary Trees

    Given two binary trees and imagine that when you put one of them to cover the other, some nodes of the two trees are overlapped while the others are not.

    You need to merge them into a new binary tree. The merge rule is that if two nodes overlap, then sum node values up as the new value of the merged node. Otherwise, the NOT null node will be used as the node of new tree.

    Example 1:

    Input: 
    	Tree 1                     Tree 2                  
              1                         2                             
             /                        /                             
            3   2                     1   3                        
           /                                                    
          5                             4   7                  
    Output: 
    Merged tree:
    	     3
    	    / 
    	   4   5
    	  /     
    	 5   4   7
    /**
     * Definition for a binary tree node.
     * function TreeNode(val) {
     *     this.val = val;
     *     this.left = this.right = null;
     * }
     */
    /**
     * @param {TreeNode} t1
     * @param {TreeNode} t2
     * @return {TreeNode}
     */
    var mergeTrees = function(t1, t2) {
        
        if (!t1 && !t2) {
            return null;
        }
        
        return helper(t1, t2);
    };
    
    function helper (t1, t2) {
        if (!t1) {
            return t2;
        }
        
        if (!t2) {
            return t1;
        }
        
        let sum = (t1.val || 0) + (t2.val || 0);
        let newNode = new TreeNode(sum);
        newNode.left = helper(t1.left, t2.left);
        newNode.right = helper(t1.right, t2.right);
        return newNode;
    }
  • 相关阅读:
    Java 泛型约束
    Java 单例模式
    Java中的Atomic包使用指南
    基数排序
    归并排序
    插入排序
    选择排序
    交换排序
    Java多线程 LockSupport
    Java并发控制:ReentrantLock Condition使用详解
  • 原文地址:https://www.cnblogs.com/Answer1215/p/12080503.html
Copyright © 2011-2022 走看看