100. Same Tree |判断二叉树相同

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.

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

	}
}