Leetcode-Same Tree

Given two binary trees, write a function to check if they are equal or not.

Two binary trees are considered equal if they are structurally identical and the nodes have the same value.

Solution:

/**
 * Definition for binary tree
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {
    public boolean isSameTree(TreeNode p, TreeNode q) {
        boolean res = isSameTreeRecur(p,q);
        
        return res;
    }
    
    public boolean isSameTreeRecur(TreeNode left, TreeNode right){
        if ((left==null&&right!=null)||(left!=null&&right==null))
            return false;
        
        if (left==null&&right==null)
            return true;
        
        if (left.val!=right.val)
            return false;
            
        if (left.left==null&&left.right==null&&right.left==null&&right.right==null)
            return true;
        
        boolean leftSame = isSameTreeRecur(left.left,right.left);
        if (!leftSame)
            return false;
            
        boolean rightSame = isSameTreeRecur(left.right,right.right);
        if (!rightSame)
            return false;
        
        return true;
    }
}

Similar to the symmetric tree problem. Need to consider every possible situation carefully.