Problem: 2050E - Three Strings
Language: java

Solution 1 (runtime: 327 ms):
import java.util.Scanner;



public class Main{

    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);

        int t = scanner.nextInt();

        scanner.nextLine(); // Consume the newline



        for (int i = 0; i < t; i++) {

            String a = scanner.nextLine();

            String b = scanner.nextLine();

            String c = scanner.nextLine();



            System.out.println(minChanges(a, b, c));

        }

    }



    private static int minChanges(String a, String b, String c) {

        int lenA = a.length();

        int lenB = b.length();

        int lenC = c.length();



        int[][] dp = new int[lenA + 1][lenB + 1];

        for (int i = 0; i <= lenA; i++) {

            for (int j = 0; j <= lenB; j++) {

                dp[i][j] = Integer.MAX_VALUE;

            }

        }

        dp[0][0] = 0;



        for (int i = 0; i <= lenA; i++) {

            for (int j = 0; j <= lenB; j++) {

                if (i > 0) {

                    dp[i][j] = Math.min(dp[i][j], dp[i - 1][j] + (a.charAt(i - 1) != c.charAt(i + j - 1) ? 1 : 0));

                }

                if (j > 0) {

                    dp[i][j] = Math.min(dp[i][j], dp[i][j - 1] + (b.charAt(j - 1) != c.charAt(i + j - 1) ? 1 : 0));

                }

            }

        }



        return dp[lenA][lenB];

    }

}





// a9JHz5LCXExByemFvIG

Solution 2 (runtime: 280 ms):
import java.util.*;

import java.lang.*;

import java.io.*;



public class Codeforces {

    public static void main(String[] args){

        FastReader fr = new FastReader();

        int tc = fr.nextInt();



        while (tc-- > 0) {

            solve(fr);

        }

    }





    private static void solve(FastReader fr) {

        String a = fr.next();

        String b = fr.next();

        String c = fr.next();

        int[][] dp = new int[a.length()+1][b.length()+1];



        for(int[] row : dp) Arrays.fill(row, -1);



        System.out.println(solve(a, b, c, 0, 0, 0, dp));

    }



    static int solve(String a, String b, String c, int i, int j, int k, int[][] dp) {

        if(k == c.length()) return 0;

        if(i > a.length() || j > b.length()) return (int)(1e7);

        boolean isAMatch = false;

        boolean isBMatch = false;



        if(dp[i][j] != -1) return dp[i][j];



        if(i < a.length() && a.charAt(i) == c.charAt(k)){

            isAMatch = true;

        }



        if(j < b.length() && b.charAt(j) == c.charAt(k)){

            isBMatch = true;

        }



        int ans1 = solve(a, b, c, i+1, j, k+1, dp) + (isAMatch ? 0 : 1);

        int ans2 = solve(a, b, c, i, j + 1, k+1, dp) + (isBMatch ? 0 : 1);



        return dp[i][j] = Math.min(ans1, ans2);

    }





    static int[] readIntArray(FastReader fr, int n){

        int[] arr = new int[n];



        for(int i = 0; i < n; i++){

            arr[i] = fr.nextInt();

        }



        return arr;

    }



    static class FastReader {

        BufferedReader br;

        StringTokenizer st;



        public FastReader() {

            br = new BufferedReader(

                    new InputStreamReader(System.in));

        }



        String next() {

            while (st == null || !st.hasMoreElements()) {

                try {

                    st = new StringTokenizer(br.readLine());

                } catch (IOException e) {

                    e.printStackTrace();

                }

            }

            return st.nextToken();

        }



        int nextInt() {

            return Integer.parseInt(next());

        }



        long nextLong() {

            return Long.parseLong(next());

        }



        double nextDouble() {

            return Double.parseDouble(next());

        }



        String nextLine() {

            String str = "";

            try {

                if (st.hasMoreTokens()) {

                    str = st.nextToken("\n");

                } else {

                    str = br.readLine();

                }

            } catch (IOException e) {

                e.printStackTrace();

            }

            return str;

        }

    }



}