Edit distance

import javafx.util.Pair;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Scanner;

public class Main {

    public static int distance(String S1, String S2) {
        // LEVENSTEIN DISTANCE

        int m = S1.length();
        int n = S2.length();

        int[] D1;
        int[] D2 = new int[n + 1];

        for(int i = 0; i <= n; i ++)
            D2[i] = i;

        for(int i = 1; i <= m; i ++) {
            D1 = D2;
            D2 = new int[n + 1];
            for(int j = 0; j <= n; j ++) {
                if(j == 0) D2[j] = i;
                else {
                    int cost = (S1.charAt(i - 1) != S2.charAt(j - 1)) ? 1 : 0;
                    if(D2[j - 1] < D1[j] && D2[j - 1] < D1[j - 1] + cost)
                        D2[j] = D2[j - 1] + 1;
                    else if(D1[j] < D1[j - 1] + cost)
                        D2[j] = D1[j] + 1;
                    else
                        D2[j] = D1[j - 1] + cost;
                }
            }
        }
        return D2[n];
    }


    public static void main(String[] args)
    {
        Scanner scanner = new Scanner(System.in);

        String first = scanner.nextLine();
        String second = scanner.nextLine();

        System.out.println(distance(first, second));
    }
}

Test 1

Verdict: UNKNOWN

Test 2

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Test 3

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Test 4

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Test 5

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Test 6

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Test 7

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Test 8

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Test 9

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Test 10

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Test 11

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Test 12

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Test 13

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Test 14

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Test 15

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Test 16

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Test 17

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Test 18

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Test 19

Verdict: UNKNOWN