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）

题解

/*
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) {
        if(pRoot1 == nullptr || pRoot2 == nullptr)
            return false;
        return isSubtree(pRoot1, pRoot2) ||
            isSubtree(pRoot1->left, pRoot2) ||
            isSubtree(pRoot1->right, pRoot2);
    }

    bool isSubtree(TreeNode* t1, TreeNode* t2) {
        if(t2 == nullptr)
            return true;
        if(t1 == nullptr)
            return false;
        if(t1->val == t2->val) {
            return isSubtree(t1->left, t2->left) &&
                isSubtree(t1->right, t2->right);
        }
        return false;
    }
};