JOIN

 Problem Statement

Problem Statement for LittleElephantAndString

### Problem Statement

Little Elephant from the Zoo of Lviv likes strings.

You are given a String A and a String B of the same length. In one turn Little Elephant can choose any character of A and move it to the beginning of the string (i.e., before the first character of A). Return the minimal number of turns needed to transform A into B. If it's impossible, return -1 instead.

### Definition

 Class: LittleElephantAndString Method: getNumber Parameters: String, String Returns: int Method signature: int getNumber(String A, String B) (be sure your method is public)

### Constraints

-A will contain between 1 and 50 characters, inclusive.
-B will contain between 1 and 50 characters, inclusive.
-A and B will be of the same length.
-A and B will consist of uppercase letters ('A'-'Z') only.

### Examples

0)

 `"ABC"` `"CBA"`
`Returns: 2`
 The optimal solution is to make two turns. On the first turn, choose character 'B' and obtain string "BAC". On the second turn, choose character 'C' and obtain "CBA".
1)

 `"A"` `"B"`
`Returns: -1`
 In this case, it's impossible to transform A into B.
2)

 `"AAABBB"` `"BBBAAA"`
`Returns: 3`
3)

 `"ABCDEFGHIJKLMNOPQRSTUVWXYZ"` `"ZYXWVUTSRQPONMLKJIHGFEDCBA"`
`Returns: 25`
4)

 `"A"` `"A"`
`Returns: 0`
5)

 `"DCABA"` `"DACBA"`
`Returns: 2`

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This problem was used for:
Single Round Match 597 Round 1 - Division I, Level One
Single Round Match 597 Round 1 - Division II, Level Two