572.subtree-of-another-tree

参考leetcode官方

dfs

class Solution {
public:
    bool isSubtree(TreeNode* s, TreeNode* t) {
        return dfs(s, t);
    }
private:
    bool dfs(TreeNode* s, TreeNode* t){
        if(!s) return false;
        return check(s,t) || dfs(s->left, t) || dfs(s->right, t);
    }
    bool check(TreeNode* s,TreeNode* t){
        if( !s&& !t) return true;
        if((!s && t)||(s && !t)||(s->val != t->val)) return false;
        return check(s->left,t->left) && check(s->right, t->right);         
    }

};