剑指offer-17.树的子结构

题目：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）

思路：这道题思路不清晰，等到理清思路再来补充



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

}
};