Difference Check

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Problem Overview

Check if two strings are anagrams or differ in exactly one character transposition.

Intuition

Check if two strings are anagrams or differ in exactly one character transposition.

Algorithm

1Count character frequency difference. If all zeros: anagram. If exactly two chars differ by symmetric amounts: single swap.

Common Pitfalls

• Sort both and compare, or use frequency array difference. Edge case: same string with repeated characters.

Difference Check.java

Java

// Approach: Sort array and check differences between consecutive elements against the threshold.
// Time: O(n log n) Space: O(1)
import java.util.*;

class Solution {
    public int minDifference(String[] arr) {
        ArrayList<Integer> ar = new ArrayList<>();
        int mid = 24 * 60 * 60, n = arr.length;
        for (int i = 0; i < n; i++) {
            String st = arr[i];
            int h = Integer.valueOf(st.substring(0, 2));
            int m = Integer.valueOf(st.substring(3, 5));
            int s = Integer.valueOf(st.substring(6, 8));
            ar.add(h * 60 * 60 + m * 60 + s);
        }

        Collections.sort(ar);
        int ans = mid;
        for (int i = 1; i < n; i++) {
            int diff = ar.get(i) - ar.get(i - 1);
            ans = Math.min(ans, diff);
            ans = Math.min(ans, (mid - ar.get(i)) + ar.get(0));
        }
        
        return ans;
    }
}

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