572.另一棵树的子树

方法：深度优先搜索暴力匹配

深度优先搜索枚举root中的每一个节点，判断这个点的子树是否与subroot相等

/*** Definition for a binary tree node.* public class TreeNode {*     int val;*     TreeNode left;*     TreeNode right;*     TreeNode() {}*     TreeNode(int val) { this.val = val; }*     TreeNode(int val, TreeNode left, TreeNode right) {*         this.val = val;*         this.left = left;*         this.right = right;*     }* }*/
class Solution {public boolean isSubtree(TreeNode root, TreeNode subRoot) {return dfs(root,subRoot);}public boolean dfs(TreeNode s,TreeNode t){if(s == null){return false;}return check(s,t) || dfs(s.left,t) || dfs(s.right,t);}public boolean check(TreeNode s,TreeNode t){if(s == null && t== null){return true;}if(s == null || t == null ||s.val != t.val){return false;}return check(s.left,t.left) && check(s.right,t.right);}
}