LeetCode:Scramble String
题目
Given a string s1, we may represent it as a binary tree by partitioning it to two non-empty substrings recursively.
Below is one possible representation of s1 = "great":
great
/ \
gr eat
/ \ / \
g r e at
/ \
a t
To scramble the string, we may choose any non-leaf node and swap its two children.
For example, if we choose the node "gr" and swap its two children, it produces a scrambled string "rgeat".
rgeat
/ \
rg eat
/ \ / \
r g e at
/ \
a t
We say that "rgeat" is a scrambled string of "great".
Similarly, if we continue to swap the children of nodes "eat" and "at", it produces a scrambled string "rgtae".
rgtae
/ \
rg tae
/ \ / \
r g ta e
/ \
t a
We say that "rgtae" is a scrambled string of "great".
Given two strings s1 and s2 of the same length, determine if s2 is a scrambled string of s1.
思路
使用递归解决，如何划分子问题?
S, T
S可能在任何一个地方分成两个子树，假如是 i, 则子树为 S[:i], S[i:]，
那么这一步，可能 scrable，也可能不 scrable。
- 如果不
scrable，子问题为 (S[:i], T[:i]), (S[i:], T[:i]) - 如果
scrable，则 S 前i个对应 T 后i个，子问题为 (S[:i], T[len-i:]), (S[i:], T[:len-i])
