출처 : https://leetcode.com/problems/permutation-difference-between-two-strings/
You are given two strings s and t such that every character occurs at most once in s and t is a permutation of s.
The permutation difference between s and t is defined as the sum of the absolute difference between the index of the occurrence of each character in s and the index of the occurrence of the same character in t.
Return the permutation difference between s and t.

class Solution {
public int findPermutationDifference(String s, String t) {
int res = 0;
for (int a = 0; a < s.length(); a++) {
res += Math.abs(a - t.indexOf(s.charAt(a)));
}
return res;
}
}