3146. Permutation Difference between Two Strings

Problem Link

Description

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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.

 

Example 1:

Input: s = "abc", t = "bac"

Output: 2

Explanation:

For s = "abc" and t = "bac", the permutation difference of s and t is equal to the sum of:

• The absolute difference between the index of the occurrence of "a" in s and the index of the occurrence of "a" in t.
• The absolute difference between the index of the occurrence of "b" in s and the index of the occurrence of "b" in t.
• The absolute difference between the index of the occurrence of "c" in s and the index of the occurrence of "c" in t.

That is, the permutation difference between s and t is equal to |0 - 1| + |1 - 0| + |2 - 2| = 2.

Example 2:

Input: s = "abcde", t = "edbac"

Output: 12

Explanation: The permutation difference between s and t is equal to |0 - 3| + |1 - 2| + |2 - 4| + |3 - 1| + |4 - 0| = 12.

 

Constraints:

• 1 <= s.length <= 26
• Each character occurs at most once in s.
• t is a permutation of s.
• s consists only of lowercase English letters.

Solution

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Python3

class Solution:
    def findPermutationDifference(self, s: str, t: str) -> int:
        mp = {x : i for i, x in enumerate(s)}
        res = 0
 
        for i, x in enumerate(t):
            res += abs(i - mp[x])
        
        return res