题解 | #树的子结构#

import java.util.*;
/**
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;

    }

}
*/
public class Solution {
    public boolean HasSubtree(TreeNode root1, TreeNode root2) {
          if(root2==null||root1==null){
          return false;
      }
      if(HasSubtree1(root1,root2)){
          return true;
      }
      return HasSubtree(root1.left,root2)||HasSubtree(root1.right,root2);
    }
    public boolean HasSubtree1(TreeNode root1, TreeNode root2) {
        if (root2 == null) {
            return  true;
        }
        if (root1 == null) {
            return false;
        }
        if (root1.val != root2.val) {
            return false;
        }
        return HasSubtree1(root1.left, root2.left) &&
               HasSubtree1(root1.right, root2.right);
    }
}