1 题目
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.
Tree Depth-first Search
public boolean isSameTree(TreeNode p,TreeNode q){ if (p == null || q == null) return (p == q); return (p.val == q.val) && isSameTree(p.left, q.left) && isSameTree(p.right, q.right); }
原文：http://www.cnblogs.com/lingtingvfengsheng/p/4448673.html