Skip to content
Related Articles

Related Articles

Minimum number of deletions so that no two consecutive are same
  • Difficulty Level : Basic
  • Last Updated : 28 May, 2018
GeeksforGeeks - Summer Carnival Banner

Given a string, find minimum number of deletions required so that there will be no two consecutive repeating characters in the string.

Examples:

Input : AAABBB
Output : 4
Explanation : New string should be AB

Input : ABABABAB
Output : 0
Explanation : There are no consecutive repeating characters.

If there are n consecutive same characters delete n-1 out of those n characters.

C++




// CPP code to count minimum deletions required
// so that there are no consecutive characters left
#include <bits/stdc++.h>
using namespace std;
  
int countDeletions(string str)
{
    int ans = 0;
    for (int i = 0; i < str.length() - 1; i++) 
         
        // If two consecutive characters are 
        // the same, delete one of them.
        if (str[i] == str[i + 1]) 
            ans++;
          
   return ans;
}
  
// Driver code
int main()
{
    string str = "AAABBB";
  
    // Function call to print answer
    cout << countDeletions(str);
  
    return 0;
}
Java



// Java code to count minimum deletions required
// so that there are no consecutive characters left
import java.util.*;
  
class GFG
{
  static int countDeletions(String s)
  {
    int ans = 0;
    char[] str = s.toCharArray();
  
    for (int i = 0; i < str.length - 1; i++) 
          
        // If two consecutive characters are 
        // the same, delete one of them.
        if (str[i] == str[i + 1]) 
            ans++;            
        
        return ans;
  }
  
    // Driver code
    public static void main(String[] args)
    {
      String str = "AAABBB";
      // Function call to print answer 
     System.out.println(countDeletions(str));
    }
}
/* This code is contributed by Mr. Somesh Awasthi */
Python



# Python code to count minimum deletions required
# so that there are no consecutive characters left\
  
def countDeletions(string):
    ans = 0
    for i in range(len(string) - 1):
          
        # If two consecutive characters are 
        # the same, delete one of them.
        if (string[i] == string[i + 1]): 
            ans += 1
          
    return ans
   
# Driver code
string = "AAABBB"
  
# Function call to print answer
print countDeletions(string)
  
# This code is contributed by Sachin Bisht
C#



// C# Program to count minimum deletions
// required so that there are no
// consecutive characters left
using System;
  
class GFG
{
      
// Function for counting deletions    
static int countDeletions(String s)
{
    int ans = 0;
    char []str = s.ToCharArray();
  
    for (int i = 0; i < str.Length - 1; i++) 
          
        // If two consecutive characters are 
        // the same, delete one of them.
        if (str[i] == str[i + 1]) 
            ans++;         
      
        return ans;
}
  
    // Driver code
    public static void Main()
    {
        String str = "AAABBB";
      
        // Function call to print answer 
        Console.Write(countDeletions(str));
    }
}
  
// This code is contributed by Nitin Mittal.
PHP



<?php
// PHP code to count minimum 
// deletions required so that
// there are no consecutive 
// characters left
  
function countDeletions($str)
{
    $ans = 0;
    for ($i = 0; $i < strlen($str) - 1; $i++) 
          
        // If two consecutive characters are 
        // the same, delete one of them.
        if ($str[$i] == $str[$i + 1]) 
            $ans++;
          
return $ans;
}
  
    // Driver Code
    $str = "AAABBB";
  
    // Function call to
    // print answer
    echo countDeletions($str);
      
// This code is contributed by nitin mittal
?>

Output:
4

This article is contributed by Rohit Thapliyal. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.
Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready.



My Personal Notes
arrow_drop_up
Previous
Minimum Cost of deletions such that string does not contains same consecutive characters
Next

Program to print all palindromes in a given range
Recommended Articles
Page :
Minimum Cost of deletions such that string does not contains same consecutive characters
27, Apr 20
Minimum insertions or deletions required to make two strings K-equivalent
19, Jan 21
Minimum number of deletions to make a string palindrome | Set 2
31, Dec 17
Minimum number of deletions to make a string palindrome
10, May 17
Minimum deletions from string to reduce it to string with at most 2 unique characters
20, Nov 18
Minimum number of elements to be removed so that pairwise consecutive elements are same
16, Nov 18
Deletions of "01" or "10" in binary string to make it free from "01" or "10"
01, Mar 19
Maximize cost of deletions to obtain string having no pair of similar adjacent characters
09, Sep 20
Minimize deletions in a Binary String to remove all subsequences of the form "0101"
19, Oct 20
Check if all bits can be made same by flipping two consecutive bits
09, Jan 20
Minimum characters that are to be inserted such that no three consecutive characters are same
30, Sep 19
Check if given strings can be made same by swapping two characters of same or different strings
07, Dec 20
Check whether two strings contain same characters in same order
31, May 19
Generate a Binary String without any consecutive 0's and at most K consecutive 1's
29, Jul 20
Count possible binary strings of length N without P consecutive 0s and Q consecutive 1s
09, Oct 20
Minimum number of pairs required to make two strings same
17, May 19
Remove consecutive alphabets which are in same case
31, Dec 18
Check if a binary string contains consecutive same or not
25, Jan 19
Group consecutive characters of same type in a string
01, Mar 19
Length of the longest substring with no consecutive same letters
08, Apr 19
Longest substring such that no three consecutive characters are same
17, Sep 19
Minimum number of characters required to be removed such that every character occurs same number of times
22, Mar 21
Minimum cost to make two strings same
28, Feb 19
Maximum number of characters between any two same character in a string
28, Oct 17
Article Contributed By :
https://media.geeksforgeeks.org/auth/avatar.png
GeeksforGeeks
Vote for difficulty
Current difficulty :
Basic





Improved By :
Article Tags :
Practice Tags :
Report Issue

We use cookies to ensure you have the best browsing experience on our website. By using our site, you
acknowledge that you have read and understood our
Cookie Policy &
        Privacy Policy

Lightbox