题目描述 输入两棵二叉树A，B，判断B是不是A的子结构。（ps：我们约定空树不是任意一个树的子结构）
解体思路
代码实现
public class Solution {
public boolean HasSubtree(TreeNode root1,TreeNode root2) {
if(root1 == null || root2 == null)
return false;
return isSubtreeWithRoot(root1, root2) || HasSubtree(root1.left, root2) || HasSubtree(root1.right, root2);
}
private boolean isSubtreeWithRoot(TreeNode root1, TreeNode root2) {
if(root2 == null)
return true;
if(root1 == null)
return false;
if(root1.val != root2.val)
return false;
return isSubtreeWithRoot(root1.left, root2.left) && isSubtreeWithRoot(root1.right, root2.right);
}
}