Alternating Characters HackerRank Solution in C, C++, Java, Python

You are given a string containing characters A and B only. Your task is to change it into a string such that there are no matching adjacent characters. To do this, you are allowed to delete zero or more characters in the string.

Your task is to find the minimum number of required deletions.

Example

s = AABAAB

Remove an A at positions 0 and 3 to make s=ABAB in 2 deletions.

Function Description

Complete the alternatingCharacters function in the editor below.

alternatingCharacters has the following parameter(s):

  • string s: a string

Returns

  • int: the minimum number of deletions required

Input Format

The first line contains an integer , the number of queries.

The next  lines each contain a string  to analyze.

Constraints

  • 1<=q<=10
  • 1<=length of s <= 10^5
  • Each string s will consist only of characters A and B.

Sample Input

5

AAAA

BBBBB

ABABABAB

BABABA

AAABBB

 

Sample Output

3

4

0

0

4

 

Explanation

The characters marked red are the ones that can be deleted so that the string does not have matching adjacent characters.

 

Alternating Characters HackerRank Solution in C

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>

int main() 
{
    int t;
    long i=0;
    unsigned int count=0;
    char * c;
    scanf("%d",&t);
    c=(char *)malloc(sizeof(char)*(100002));
    while(t--)
    {
        scanf("%s",c);
        for(i=0; *(c+i); i++)
        {
            if(c[i]==c[i+1])
            {
                count++;
            }
        }
        printf("%u\n",count);
        count=0;
    }
      
    return 0;
}

 

Alternating Characters HackerRank Solution in C++

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    int t;
    cin>>t;
    while(t--)
        {
        string s;int c=0,a=0;
        cin>>s;
        for(int i=1;s[i]!='\0';i++)
            {
            if((s[i]==65 && s[a]==66)||(s[i]==66 &&s[a]==65))
            {
                a=i;
               // cout<<a<<endl;
               }
                else{
                    c++;
                    //cout<<c<<" "<<i<<endl;
                   
                }
                
            }
        cout<<c<<endl;
        
    }
    return 0;
}

 

Alternating Characters HackerRank Solution in Java

import java.util.Scanner;
public class Solution {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner s = new Scanner(System.in);
        int t = s.nextInt();
        s.nextLine();
        while(t-- > 0)
        {
            int count = 0;
            String str = s.nextLine();
            for(int i=1;i<str.length();i++)
            {
                if(str.charAt(i)==str.charAt(i-1))
                {
                    count++;
                }
            }
            System.out.println(count);	
        }
    }

}

 

Alternating Characters HackerRank Solution in Python

t = int(raw_input())
for j in range(t):
    res=0
    str = raw_input()
    if 'A' not in str or 'B' not in str:
        res = len(str)-1
        print res
        continue
    i=0
    while i<(len(str)-1):
        if str[i+1]==str[i]:
            res+=1
        i+=1
    print res

 

Alternating Characters HackerRank Solution in C#

using System;

namespace AlternatingCharacters
{
    class Program
    {
        static void Main(string[] args)
        {
            int t = int.Parse(Console.ReadLine());
            for (int i = 0; i < t; i++)
            {
                HandleTestCase();
            }
        }

        static void HandleTestCase()
        {
            string str = Console.ReadLine();
            int deletions = 0;
            char lastChar = 'C';
            for (int i = 0; i < str.Length; i++)
            {
                if (str[i] == lastChar)
                {
                    deletions++;
                }
                lastChar = str[i];
            }

            Console.WriteLine(deletions);
        }
    }
}

 

Alternating Characters HackerRank Challenge

Link – https://www.hackerrank.com/challenges/alternating-characters/

Next HackerRank Challenge Solution 

Link – https://exploringbits.com/the-full-counting-sort-hackerrank-solution/

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