树的子结构

题目描述

输入两棵二叉树A，B，判断B是不是A的子结构。（ps：我们约定空树不是任意一个树的子结构）

/*
struct TreeNode {
	int val;
	struct TreeNode *left;
	struct TreeNode *right;
	TreeNode(int x) :
			val(x), left(NULL), right(NULL) {
	}
};*/
class Solution {
public:
    bool HasSubtree(TreeNode* pRoot1, TreeNode* pRoot2)
    {
        bool flag = false;
        if(pRoot1 != NULL && pRoot2 != NULL)
        {
            if(pRoot1->val == pRoot2->val)
            {
                flag = isSubtree(pRoot1,pRoot2);
            }
            if(!flag)
            {
                flag = HasSubtree(pRoot1->left,pRoot2);
            }
            if(!flag)
            {
                flag = HasSubtree(pRoot1->right,pRoot2);
            }
        }    
        return flag;
    }
    
    bool isSubtree(TreeNode* pRoot1, TreeNode* pRoot2)
    {
        if(pRoot2 == NULL) return true;
        if(pRoot1 == NULL) return false;
        if(pRoot1->val == pRoot2->val)
        {
            return isSubtree(pRoot1->left,pRoot2->left) && isSubtree(pRoot1->right,pRoot2->right);
        }
        return false;
    }
};