# Minimum number of additons to make the string balanced

Given a string str of lowercase characters, the task is to find the minimum number of characters that need to added to the string in order to make it balanced. A string is said to be balanced if and only if the number of occurrences of each of the characters is equal.

Examples:

Input: str = “geeksforgeeks”
Output: 15
Add 2 ‘g’, 2 ‘k’, 2 ‘s’, 3 ‘f’, 3 ‘o’ and 3 ‘r’.

Input: str = “abcd”
Output: 0

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach: In order to minimize the additions required, every character’s frequency must be made equal to the frequency of the element occurring most frequently. So first, create a frequency array and find the frequency of all the characters of the given string. Now, the required answer will be the sum of the absolute differences of the frequency of every character with the maximum frequency from the frequency array.

Below is the implementation of the above approach:

## C++

 // C++ implementation of the approach #include using namespace std;    #define MAX 26    // Function to return the minimum additions // required to balance the given string int minimumAddition(string str, int len) {        // To store the frequency of     // the characters of str     int freq[MAX] = { 0 };        // Update the frequency of the characters     for (int i = 0; i < len; i++) {         freq[str[i] - 'a']++;     }        // To store the maximum frequency from the array     int maxFreq = *max_element(freq, freq + MAX);        // To store the minimum additions required     int minAddition = 0;     for (int i = 0; i < MAX; i++) {            // Every character's frequency must be         // equal to the frequency of the most         // frequently occurring character         if (freq[i] > 0) {             minAddition += abs(maxFreq - freq[i]);         }     }        return minAddition; }    // Driver code int main() {     string str = "geeksforgeeks";     int len = str.length();        cout << minimumAddition(str, len);        return 0; }

## Java

 // Java implementation of the approach  class GFG  {     final static int MAX = 26;             static int max_element(int freq[])     {         int max_ele = freq[0];         for(int i = 0; i < MAX; i++)         {             if(max_ele < freq[i])                 max_ele = freq[i];         }         return max_ele;     }            // Function to return the minimum additions      // required to balance the given string      static int minimumAddition(String str, int len)      {                 // To store the frequency of          // the characters of str          int freq[] = new int[MAX];                // Update the frequency of the characters          for (int i = 0; i < len; i++)          {              freq[str.charAt(i) - 'a']++;          }                 // To store the maximum frequency from the array          int maxFreq = max_element(freq);                 // To store the minimum additions required          int minAddition = 0;          for (int i = 0; i < MAX; i++)          {                     // Every character's frequency must be              // equal to the frequency of the most              // frequently occurring character              if (freq[i] > 0)              {                  minAddition += Math.abs(maxFreq - freq[i]);              }          }          return minAddition;      }             // Driver code      public static void main (String[] args)     {          String str = "geeksforgeeks";          int len = str.length();                 System.out.println(minimumAddition(str, len));      }  }    // This code is contributed by AnkitRai01

## Python3

 # Python3 implementation of the approach MAX = 26    # Function to return the minimum additions # required to balance the given str1ing def minimumAddition(str1, Len):        # To store the frequency of     # the characters of str1     freq = [0 for i in range(MAX)]        # Update the frequency of the characters     for i in range(Len):         freq[ord(str1[i]) - ord('a')] += 1        # To store the maximum frequency from the array     maxFreq = max(freq)        # To store the minimum additions required     minAddition = 0     for i in range(MAX):            # Every character's frequency must be         # equal to the frequency of the most         # frequently occurring character         if (freq[i] > 0):             minAddition += abs(maxFreq - freq[i])        return minAddition    # Driver code str1 = "geeksforgeeks" Len = len(str1)    print(minimumAddition(str1, Len))    # This code is contributed Mohit Kumar

## C#

 // C# implementation of the approach using System;        class GFG  {     static int MAX = 26;             static int max_element(int []freq)     {         int max_ele = freq[0];         for(int i = 0; i < MAX; i++)         {             if(max_ele < freq[i])                 max_ele = freq[i];         }         return max_ele;     }            // Function to return the minimum additions      // required to balance the given string      static int minimumAddition(String str, int len)      {                 // To store the frequency of          // the characters of str          int []freq = new int[MAX];                // Update the frequency of the characters          for (int i = 0; i < len; i++)          {              freq[str[i] - 'a']++;          }                 // To store the maximum frequency from the array          int maxFreq = max_element(freq);                 // To store the minimum additions required          int minAddition = 0;          for (int i = 0; i < MAX; i++)          {                     // Every character's frequency must be              // equal to the frequency of the most              // frequently occurring character              if (freq[i] > 0)              {                  minAddition += Math.Abs(maxFreq - freq[i]);              }          }          return minAddition;      }             // Driver code      public static void Main (String[] args)     {          String str = "geeksforgeeks";          int len = str.Length;                 Console.WriteLine(minimumAddition(str, len));      }  }    // This code is contributed by 29AjayKumar

Output:

15

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