【二叉树】一棵树的子树是一颗树

题目链接：https://leetcode.com/problems/subtree-of-another-tree/#/description

/** * 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(s->val==t->val){            return isSameTree(s,t)||isSubtree(s->left,t)||isSubtree(s->right,t);        }else{            return isSubtree(s->left,t)||isSubtree(s->right,t);        }    }    //  判断两棵树是不是相同    bool isSameTree(TreeNode* p, TreeNode* q) {          if(p==NULL && q==NULL){              return true;          }else if((p==NULL&&q!=NULL)||(p!=NULL&&q==NULL)||(q->val!=p->val)){              return false;          }else{              bool tmp=isSameTree(p->left,q->left);              bool tmp1=isSameTree(p->right,q->right);              if(tmp&&tmp1) return true;              else return false;          }      } };