SameTree.java

/**
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 binary tree
 * public class TreeNode {
 * int val;
 * TreeNode left;
 * TreeNode right;
 * TreeNode(int x) { val = x; }
 * }
 */

public class SameTree {
 public boolean isSameTree(TreeNode p, TreeNode q) {
 if (p == q) return true;
 if (p == null ^ q == null) return false;
 return p.val == q.val && isSameTree(p.left, q.left) && isSameTree(p.right, q.right);
 }
}