c_cpp 572.cpp

Posted 2021-05-14

/**
 * 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 isSubtree(TreeNode* s, TreeNode* t) {
        if (s == NULL)  return false;
        if (isEqual(s, t))
            return true;
        else
            return isSubtree(s->left, t) || isSubtree(s->right, t);
    }
    
    bool isEqual(TreeNode* s, TreeNode* t) {
        if (s == NULL && t == NULL) 
            return true;
        else if (s != NULL && t != NULL)
            return (s->val == t->val) && isEqual(s->left, t->left) && isEqual(s->right, t->right);
        else
            return false;
    }
};