Problem: 2050E - Three Strings
Language: java

Solution 1 (runtime: 296 ms):
//package codeforcesques;
import java.util.*;
import java.io.*;
public class ThreeStrings {
    int mincount = Integer.MAX_VALUE;

    public static void main(String[] args) {
        FastReader fs = new FastReader();

        int t = fs.nextInt();

        while (t-- > 0) {
            String s1 = fs.nextLine();
            String s2 = fs.nextLine();
            String s3 = fs.nextLine();
            ThreeStrings d = new ThreeStrings();
            int[][] dp = new int[s1.length()][s2.length()];
            for (int i = 0; i < s1.length(); i++) {
                Arrays.fill(dp[i], -1);
            }
            System.out.println( s3.length()-rec(0, 0, 0, s1, s2, s3, dp));
        }
    }
    public static int rec(int n, int i, int j, String a, String b, String c, int[][] dp) {
        if (i == a.length()) {
            int val = 0;
            while (j < b.length()) {
                if (b.charAt(j) == c.charAt(n)) {
                    val++;
                }
                j++;
                n++;
            }
            return val;
        }
        if (j == b.length()) {
            int val = 0;
            while (i < a.length()) {
                if (a.charAt(i) == c.charAt(n)) {
                    val++;
                }
                i++;
                n++;
            }
            return val;
        }
        if (dp[i][j] != -1) {
            return dp[i][j];
        }
        int c1 = 0;
        int c2 = 0;
        if (a.charAt(i) == c.charAt(n)) {
            c1++;
        }
        if (b.charAt(j) == c.charAt(n)) {
            c2++;
        }
        int max1 = rec(n + 1, i + 1, j, a, b, c, dp) + c1;
        int max2 = rec(n + 1, i, j + 1, a, b, c, dp) + c2;
        dp[i][j] = Math.max(max1, max2);
        return dp[i][j];
    }
}
class FastReader {
    BufferedReader gt;
    StringTokenizer st;

    public FastReader() {
        gt = new BufferedReader(new InputStreamReader(System.in));
    }

    String next() {
        while (st == null || !st.hasMoreElements()) {
            try {
                st = new StringTokenizer(gt.readLine());
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return st.nextToken();
    }

    String nextLine() {
        String str = "";
        try {
            str = gt.readLine();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return str;
    }

    int nextInt() {
        return Integer.parseInt(next());
    }

    int[] readIntArray(int n) {
        int[] res = new int[n];
        for (int i = 0; i < n; i++)
            res[i] = nextInt();
        return res;
    }

    long nextLong() {
        return Long.parseLong(next());
    }

    long[] readLongArray(int n) {
        long[] res = new long[n];
        for (int i = 0; i < n; i++)
            res[i] = nextLong();
        return res;
    }

    String[] readStringArray(int n) {
        String[] str = new String[n];
        for (int i = 0; i < n; i++)
            str[i] = nextLine();

        return str;
    }

    int getGCD(int a, int b) {
        if (b == 0)
            return a;
        else
            return getGCD(b, a % b);
    }
}

Solution 2 (runtime: 390 ms):
import java.util.*;

public class Q1 {
    public static long solve(long n, HashMap<Long, Long> map) {
        if (n <= 3) {
            return 1;
        }

        if (map.containsKey(n)) {
            return map.get(n);
        }

        long count = solve(n / 4, map) + solve(n / 4, map);
        map.put(n, count);
        return map.get(n);
    }

    public static long gcd(long a, long b) {
        if (a == 0)
            return b;
        if (b == 0)
            return a;

        // Base case
        if (a == b)
            return a;

        // a is greater
        if (a > b) {
            if (a % b == 0)
                return b;
            return gcd(a - b, b);
        }
        if (b % a == 0)
            return a;
        return gcd(a, b - a);
    }

    public static int solve(int ai, int ci, String a, String b, String c, int dp[][]) {
        int bi = ci - ai;
        if (ai == a.length()) {
            String s1 = b.substring(bi);
            String s2 = c.substring(ci);
            if (s1.equals(s2)) {
                return 0;
            }
            int cnt = 0;
            for (int i = 0; i < s1.length(); i++) {
                if (s1.charAt(i) != s2.charAt(i)) {
                    cnt++;
                }
            }

            return cnt;
        }

        if (bi == b.length()) {
            String s1 = a.substring(ai);
            String s2 = c.substring(ci);
            if (s1.equals(s2)) {
                return 0;
            }
            int cnt = 0;
            for (int i = 0; i < s1.length(); i++) {
                if (s1.charAt(i) != s2.charAt(i)) {
                    cnt++;
                }
            }

            return cnt;
        }

        if (dp[ai][ci] != -1) {
            return dp[ai][ci];
        }

        int min = Integer.MAX_VALUE;
        if (a.charAt(ai) == c.charAt(ci)) {
            min = Math.min(solve(ai + 1, ci + 1, a, b, c, dp), min);
        }

        if (b.charAt(bi) == c.charAt(ci)) {
            min = Math.min(solve(ai, ci + 1, a, b, c, dp), min);
        }

        if (a.charAt(ai) != c.charAt(ci) || b.charAt(bi) != c.charAt(ci)) {
            min = Math.min(1 + Math.min(solve(ai + 1, ci + 1, a, b, c, dp), solve(ai, ci + 1, a, b, c, dp)), min);
        }

        return dp[ai][ci] = min;
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int t = sc.nextInt();
        while (t-- > 0) {
            String a = sc.next();
            String b = sc.next();
            String c = sc.next();
            int dp[][] = new int[a.length()][c.length()];
            for (int row[] : dp) {
                Arrays.fill(row, -1);
            }
            System.out.println(solve(0, 0, a, b, c, dp));
        }
    }
}