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.

分析：對于二叉樹這一具有天然遞歸特性的資料結構，首先想到的就應該是遞歸，既然是遞歸，最重要就是邊界了