Common Child in Algorithm | HackerRank Programming Solutions | HackerRank Problem Solving Solutions in Java [💯Correct]

Hello Programmers/Coders, Today we are going to share solutions of Programming problems of HackerRank, Algorithm Solutions of Problem Solving Section in Java. At Each Problem with Successful submission with all Test Cases Passed, you will get an score or marks. And after solving maximum problems, you will be getting stars. This will highlight your profile to the recruiters.

In this post, you will find the solution for Common Child in Java-HackerRank Problem. We are providing the correct and tested solutions of coding problems present on HackerRank. If you are not able to solve any problem, then you can take help from our Blog/website.

Use “Ctrl+F” To Find Any Questions Answer. & For Mobile User, You Just Need To Click On Three dots In Your Browser & You Will Get A “Find” Option There. Use These Option to Get Any Random Questions Answer.

Introduction To Algorithm

The word Algorithm means “a process or set of rules to be followed in calculations or other problem-solving operations”. Therefore Algorithm refers to a set of rules/instructions that step-by-step define how a work is to be executed upon in order to get the expected results. 

Advantages of Algorithms:

• It is easy to understand.
• Algorithm is a step-wise representation of a solution to a given problem.
• In Algorithm the problem is broken down into smaller pieces or steps hence, it is easier for the programmer to convert it into an actual program.

Link for the Problem – Common Child – Hacker Rank Solution

Common Child – Hacker Rank Solution

Problem:

A string is said to be a child of a another string if it can be formed by deleting 0 or more characters from the other string. Letters cannot be rearranged. Given two strings of equal length, what’s the longest string that can be constructed such that it is a child of both?

Example

These strings have two children with maximum length 3, ABC and ABD. They can be formed by eliminating either the D or C from both strings. Return .

Function Description

Complete the commonChild function in the editor below.

commonChild has the following parameter(s):

• string s1: a string
• string s2: another string

Returns

• int: the length of the longest string which is a common child of the input strings

Input Format

There are two lines, each with a string,  and .

Constraints

•  where  means “the length of “
• All characters are upper case in the range ascii[A-Z].

Sample Input

HARRY
SALLY

Sample Output

 2

Explanation

The longest string that can be formed by deleting zero or more characters from  and  is , whose length is 2.

Sample Input 1

AA
BB

Sample Output 1

0

Explanation 1

 and  have no characters in common and hence the output is 0.

Sample Input 2

SHINCHAN
NOHARAAA

Sample Output 2

3

Explanation 2

The longest string that can be formed between  and  while maintaining the order is .

Sample Input 3

ABCDEF
FBDAMN

Sample Output 3

2

Explanation 3
 is the longest child of the given strings.

Common Child – Hacker Rank Solution

import java.util.Scanner;

public class CommonChild {

	static int commonChild(String s1, String s2) {
		return LCSM4(s1.toCharArray(), s2.toCharArray(), s1.length(), s2.length());

	}

	public static int LCSM4(char[] X, char[] Y, int m, int n) {
		int memo[] = new int[n + 1];

		for (int i = 1; i <= m; i++) {
			int prev = 0;
			for (int j = 1; j <= n; j++) {
				int temp = memo[j];
				if (X[i - 1] == Y[j - 1]) {
					memo[j] = prev + 1;
				} else {
					memo[j] = Math.max(memo[j], memo[j - 1]);
				}
				prev = temp;
			}

		}
		return memo[n];
	}

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s1 = sc.next();
		String s2 = sc.next();
		int result = commonChild(s1, s2);
		System.out.println(result);
		sc.close();
	}

}