3146. 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) {
        unordered_map<char,int> freq;
        for(int i = 0; i < s.length(); i++) freq[s[i]] = i;
        int res = 0;
        for(int i = 0; i < t.length(); i++) {
            res += abs(freq[t[i]] - i);
        }
        return res;
    }
};