面试题18 树的子结构

题目描述

/*
struct TreeNode {
int val;
struct TreeNode *left;
struct TreeNode *right;
TreeNode(int x) :
val(x), left(NULL), right(NULL) {
}
};*/
class Solution {
public:
bool DoesTree1hasTree2(TreeNode* pRoot1, TreeNode* pRoot2){
if (pRoot2 == NULL){
return true;
}
if (pRoot1 == NULL){
return false;
}
if (pRoot1->val != pRoot2->val){
return false;
}
return DoesTree1hasTree2(pRoot1->left, pRoot2->left) && DoesTree1hasTree2(pRoot1->right, pRoot2->right);
}

bool HasSubtree(TreeNode* pRootA, TreeNode* pRootB)
{
if (pRootA == NULL || pRootB == NULL)
return false;
return DoesTree1hasTree2(pRootA, pRootB) ||
HasSubtree(pRootA->left, pRootB) ||
HasSubtree(pRootA->right, pRootB);
}
};