Check Reverse Sublist to Form Another List in Python

Suppose we have two lists of numbers called A, and B. We have to take some sublist in A and reverse it. Then check whether it is possible to turn A into B or not. We can take sublist and reverse it any number of times.

So, if the input is like A = [2, 3, 4, 9, 10], B = [4, 3, 2, 10, 9], then the output will be True as we can reverse [2,3,4] and [9,10].

To solve this, we will follow these steps −

• res := a map, initially empty
• for each n in nums, do
  • res[n] := res[n] + 1
• for each t in target, do
  • res[t] := res[t] - 1
• return true when all elements in the values of res is same as 0.

Let us see the following implementation to get better understanding −

Example

 Live Demo

from collections import defaultdict
class Solution:
   def solve(self, nums, target):
      res = defaultdict(int)
      for n in nums:
         res[n] += 1
      for t in target:
         res[t] -= 1
      return all(n == 0 for n in res.values())
ob = Solution()
A = [2, 3, 4, 9, 10]
B = [4, 3, 2, 10, 9]
print(ob.solve(A, B))

Input

[2, 3, 4, 9, 10], [4, 3, 2, 10, 9]

Output

True