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