[LeetCode] 572. Subtree of Another Tree

轉自LeetCode

Given two non-empty binary trees s and t, check whether tree t has exactly the same structure and node values with a subtree of s. A subtree of s is a tree consists of a node in s and all of this node's descendants. The tree s could also be considered as a subtree of itself.

Example 1:
Given tree s:

     3
    / \
   4   5
  / \
 1   2

Given tree t:

   4 
  / \
 1   2

Return true, because t has the same structure and node values with a subtree of s.

Example 2:
Given tree s:

     3
    / \
   4   5
  / \
 1   2
    /
   0

Given tree t:

   4
  / \
 1   2

Return false.

<Solution>

和 100. Same Tree 類似，但變成是要找 subRoot tree，需要點變化

想法如下

• 這題直覺是要用遞迴解，因為過程中會需要返回上層再做一次檢查

• 歷遍 tree s，把每個 node 都當作 root，去和 t 比對，看看是否相等。不相等，就繼續遞迴找

code 如下

C++(參考答案)

Java

kotlin