题解 | #合并二叉树#

import java.util.*;

/*
 * public class TreeNode {
 *   int val = 0;
 *   TreeNode left = null;
 *   TreeNode right = null;
 *   public TreeNode(int val) {
 *     this.val = val;
 *   }
 * }
 */

public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param t1 TreeNode类 
     * @param t2 TreeNode类 
     * @return TreeNode类
     */
    public TreeNode mergeTrees (TreeNode t1, TreeNode t2) {
        if(t1==null&&t2!=null){
            return t2;
        }
        if(t1!=null&&t2==null){
            return t1;
        }
        if(t1==null&&t2==null){
            return null;
        }
        //创建一个新的树赋值过去
        TreeNode t = new TreeNode(t1.val+t2.val);
       t.left = mergeTrees(t1.left,t2.left);
        t.right=mergeTrees(t1.right,t2.right);



        return t;
    }
}