Strings: Remove all consecutive duplicates from the string

Problem Statement:

Given a string, remove all the consecutive duplicates

Example

Input : aaaaabbbbbb
Output : ab

Solution

Solution is very simple.

If the string is empty return.

else, compare the adjacent character of the string. If they are same then shift the character one to the left, call recursion on string s.

If not same, call the recursion from the next character s+1

Time complexity will be O(n^2)

Solution in C++

#include <vector>    
#include <algorithm>  
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#include <iostream>    
#include <string>

using namespace std;


void remove_duplicates(char* S) 
{ 
    // if string is empty, return 
    if (S[0] == '\0') 
        return; 
  
    // check if adjacent characters are same 
    if (S[0] == S[1]) 
    { 
          
        // Shift character by one to left 
        int i = 0;  
        while (S[i] != '\0') 
        { 
            S[i] = S[i + 1]; 
            i++; 
        } 
  
        // Check on updated S 
        remove_duplicates(S); 
    } 
  
    // If the adjacent characters are not same check from S+1 string  
    remove_duplicates(S + 1); 
} 

int main()
{
  char s[]  = "hellooo";
  remove_duplicates(s);
  cout << s << endl; 

}

Output:

helo