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面试题 04.10. 检查子树

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Symbols count in article: 1.3k Reading time ≈ 1 mins.

面试题 04.10. 检查子树

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/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    bool checkSubTree(TreeNode* t1, TreeNode* t2) {
        queue<TreeNode*> q;
        q.push(t1);
        while(!q.empty())
        {
            auto p = q.front();
            q.pop();
            if(check(p, t2))
                return true;
            if(p->left)
                q.push(p->left);
            if(p->right)
                q.push(p->right);
        }
        return false;
    }
private:
    bool check(TreeNode* t1, TreeNode* t2)
    {
        if(!t1)
            return !t2;
        if(!t2)
            return !t1;
        if(t1->val != t2->val)
            return false;
        return check(t1->left, t2->left) && check(t1->right, t2->right);
    }
};

递归改

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/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    bool checkSubTree(TreeNode* t1, TreeNode* t2) {
        if(!t1)
            return !t2;
        return check(t1, t2) || checkSubTree(t1->left, t2) || checkSubTree(t1->right, t2);
    }
private:
    bool check(TreeNode* t1, TreeNode* t2)
    {
        if(!t1)
            return !t2;
        if(!t2)
            return !t1;
        if(t1->val != t2->val)
            return false;
        return check(t1->left, t2->left) && check(t1->right, t2->right);
    }
};