100. 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.

题目含义：判断两个二进制树结构是否相等

    public boolean sameTree(TreeNode p, TreeNode q)
    {
        if (p==null && q==null) return true;
        if (p==null || q==null) return false;
        if (p.val != q.val) return false;
        return sameTree(p.left,q.left) && sameTree(p.right,q.right);
    } 
    public boolean isSameTree(TreeNode p, TreeNode q) {
        return sameTree(p,q);        
    }