Common Child – HackerRank Solution

In this post, we will solve Common Child HackerRank Solution. This problem (Common Child) is a part of HackerRank Problem Solving series.

Solution – Common Child – HackerRank Solution

C++

#include <bits/stdc++.h>

using namespace std;

// Complete the commonChild function below.
int commonChild(string s1, string s2) {
    int iLen1 = s1.length();
    int iLen2 = s2.length();
    vector<vector<int>> vMatrix(iLen2 + 1, vector<int>(iLen1 + 1, 0));
    
    for (int i = 1; i <= iLen2; ++i) {
        for (int j = 1; j <= iLen1; ++j) {
            if ( s2[i - 1] == s1[j - 1] ) {
                vMatrix[i][j] = vMatrix[i-1][j-1] + 1;
            }
            else {
                vMatrix[i][j] = max(vMatrix[i-1][j], vMatrix[i][j-1]);
            }
        }
    }
    return vMatrix[iLen2][iLen1];
}

int main()
{
    ofstream fout(getenv("OUTPUT_PATH"));

    string s1;
    getline(cin, s1);

    string s2;
    getline(cin, s2);

    int result = commonChild(s1, s2);

    fout << result << "\n";

    fout.close();

    return 0;
}

Python

import os

# Complete the commonChild function below.
def commonChild(s1, s2):
  maxAt = {}

  for i1 in range(len(s1)):
    maxForI1 = 0
    for i2 in range(len(s2)):
      potentialSum = maxForI1 + 1

      # You might be tempted to use the max() function to simplify the next three lines,
      # but that makes the solution so much slower that several of the test cases fail.
      other = maxAt.get(i2, 0)
      if other > maxForI1:
        maxForI1 = other

      if s1[i1] == s2[i2]:
        maxAt[i2] = potentialSum

  return max(maxAt.values(), default=0)

if __name__ == '__main__':
    fptr = open(os.environ['OUTPUT_PATH'], 'w')

    s1 = input()

    s2 = input()

    result = commonChild(s1, s2)

    fptr.write(str(result) + '\n')

    fptr.close()

Java

import java.io.*;
import java.util.*;

public class Solution {
    public int child(String str1, String str2){
        int L[][] = new int[str1.length()+1][str2.length()+1];
        for(int i=0;i<=str1.length();i++){
            for(int j=0;j<=str2.length();j++){
                if(i==0 || j==0)
                    L[i][j]=0;
                else if(str1.charAt(i-1)==str2.charAt(j-1)){
                    L[i][j] = L[i-1][j-1]+1;
                }
                else{
                    L[i][j] = Math.max(L[i-1][j],L[i][j-1]);
                }
            }
        }
        return L[str1.length()][str2.length()];
    }
    public static void main(String[] args){
        Solution ob = new Solution();
        Scanner sc = new Scanner(System.in);
        String str1 = sc.nextLine();
        String str2 = sc.nextLine();
        int ans = ob.child(str1,str2);
        System.out.println(ans);
       
    }
}

Note: This problem (Common Child) is generated by HackerRank but the solution is provided by CodingBroz. This tutorial is only for Educational and Learning purpose.