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）
思路
- 遍历父结构
- 判断子结构是否相同
class TreeNode:
def __init__(self, x):
self.val = x
self.left = None
self.right = None
def helper(treeA, treeB):
if not treeB:
return True
elif not treeA:
return False
elif treeA.val != treeB.val:
return False
else:
return helper(treeA.left, treeB.left) and helper(treeA.right, treeB.right)
def HasSubtree(pRoot1, pRoot2):
# write code here
if not pRoot1 or not pRoot2: return False
# 2 是不是 1的子树
res = False
if pRoot1.val == pRoot2.val:
res = helper(pRoot1, pRoot2)
if res:
return True
else:
return HasSubtree(pRoot1.left, pRoot2) or HasSubtree(pRoot1.right, pRoot2)