Maximum occurring lexicographically smallest character in a String

Last Updated : 28 Nov, 2022

Given a string containing lowercase characters. The task is to print the maximum occurring character in the input string. If 2 or more characters appear the same number of times, print the lexicographically (alphabetically) lowest (first) character.

Examples:

Input: test sample
Output: e
Explanation: e’t’, ‘e’ and ‘s’ appears 2 times, but ‘e’ is the lexicographically smallest character.

Input: sample program
Output: a

In the previous article, if there are more than one character occurring the maximum number of time, then any of the characters is returned. In this post, the lexicographically smallest character of all the characters is returned.
Approach: Declare a freq[26] array which is used as a hash table to store the frequencies of each character in the input string. Iterate in the string and increase the count of freq[s[i]] for every character. Traverse the freq[] array from left to right and keep track of the character having the maximum frequency so far. The value at freq[i] represents the frequency of character (i + ‘a’).

Below is the implementation of the above approach:

C++

// C++ implementation to find 
// the maximum occurring character in 
// an input string which is lexicographically first 
#include <bits/stdc++.h> 
using namespace std; 
  
// function to find the maximum occurring character in 
// an input string which is lexicographically first 
char getMaxOccurringChar(char str[]) 
{ 
    // freq[] used as hash table 
    int freq[26] = { 0 }; 
  
    // to store maximum frequency 
    int max = -1; 
  
    // to store the maximum occurring character 
    char result; 
  
    // length of 'str' 
    int len = strlen(str); 
  
    // get frequency of each character of 'str' 
    for (int i = 0; i < len; i++) 
        freq[str[i] - 'a']++; 
  
    // for each character, where character is obtained by 
    // (i + 'a') check whether it is the maximum character 
    // so far and accordingly update 'result' 
    for (int i = 0; i < 26; i++) 
        if (max < freq[i]) { 
            max = freq[i]; 
            result = (char)(i + 'a'); 
        } 
  
    // maximum occurring character 
    return result; 
} 
  
// Driver Code 
int main() 
{ 
    char str[] = "sample program"; 
    cout << "Maximum occurring character = "
         << getMaxOccurringChar(str); 
    return 0; 
} 

Java

// Java implementation to find 
// the maximum occurring character in 
// an input string which is lexicographically first 
  
class GFG { 
  
// function to find the maximum occurring character in 
// an input string which is lexicographically first 
    static char getMaxOccurringChar(char str[]) { 
        // freq[] used as hash table 
        int freq[] = new int[26]; 
  
        // to store maximum frequency 
        int max = -1; 
  
        // to store the maximum occurring character 
        char result = 0; 
  
        // length of 'str' 
        int len = str.length; 
  
        // get frequency of each character of 'str' 
        for (int i = 0; i < len; i++) { 
            if (str[i] != ' ') { 
                freq[str[i] - 'a']++; 
            } 
        } 
  
        // for each character, where character is obtained by 
        // (i + 'a') check whether it is the maximum character 
        // so far and accordingly update 'result' 
        for (int i = 0; i < 26; i++) { 
            if (max < freq[i]) { 
                max = freq[i]; 
                result = (char) (i + 'a'); 
            } 
        } 
  
        // maximum occurring character 
        return result; 
    } 
  
// Driver Code 
    public static void main(String[] args) { 
        char str[] = "sample program".toCharArray(); 
        System.out.println("Maximum occurring character = "
                + getMaxOccurringChar(str)); 
    } 
}  
  
// This code is contributed by 29AjayKumar  

Python3

# Python 3 implementation to find the  
# maximum occurring character in an input  
# string which is lexicographically first 
  
# function to find the maximum occurring  
# character in an input string which is  
# lexicographically first 
def getMaxOccurringChar(str): 
      
    # freq[] used as hash table 
    freq = [0 for i in range(100)]  
  
    # to store maximum frequency 
    max = -1
  
    # to store the maximum occurring 
    # character length of 'str' 
    len__ = len(str) 
  
    # get frequency of each character of 'str' 
    for i in range(0, len__, 1): 
        freq[ord(str[i]) - ord('a')] += 1
  
    # for each character, where character 
    # is obtained by (i + 'a') check whether  
    # it is the maximum character so far and 
    # accordingly update 'result' 
    for i in range(26): 
        if (max < freq[i]): 
            max = freq[i] 
            result = chr(ord('a') + i) 
  
    # maximum occurring character 
    return result 
  
# Driver Code 
if __name__ == '__main__': 
    str = "sample program"
    print("Maximum occurring character =", 
                 getMaxOccurringChar(str)) 
      
# This code is contributed by 
# Surendra_Gangwar 

C#

// C# implementation to find 
// the maximum occurring character in 
// an input string which is lexicographically first 
   
using System; 
class GFG { 
   
// function to find the maximum occurring character in 
// an input string which is lexicographically first 
    static char getMaxOccurringChar(string str) { 
        // freq[] used as hash table 
        int[] freq = new int[26]; 
   
        // to store maximum frequency 
        int max = -1; 
   
        // to store the maximum occurring character 
        char result = (char)0; 
   
        // length of 'str' 
        int len = str.Length; 
   
        // get frequency of each character of 'str' 
        for (int i = 0; i < len; i++) { 
            if (str[i] != ' ') { 
                freq[str[i] - 'a']++; 
            } 
        } 
   
        // for each character, where character is obtained by 
        // (i + 'a') check whether it is the maximum character 
        // so far and accordingly update 'result' 
        for (int i = 0; i < 26; i++) { 
            if (max < freq[i]) { 
                max = freq[i]; 
                result = (char) (i + 'a'); 
            } 
        } 
   
        // maximum occurring character 
        return result; 
    } 
   
// Driver Code 
    public static void Main() { 
        string str = "sample program"; 
        Console.WriteLine("Maximum occurring character = "
                + getMaxOccurringChar(str)); 
    } 
}  
  

Javascript

// C# implementation to find 
// the maximum occurring character in 
// an input string which is lexicographically first 
   
using System; 
class GFG { 
   
// function to find the maximum occurring character in 
// an input string which is lexicographically first 
    static char getMaxOccurringChar(string str) { 
        // freq[] used as hash table 
        int[] freq = new int[26]; 
   
        // to store maximum frequency 
        int max = -1; 
   
        // to store the maximum occurring character 
        char result = (char)0; 
   
        // length of 'str' 
        int len = str.Length; 
   
        // get frequency of each character of 'str' 
        for (int i = 0; i < len; i++) { 
            if (str[i] != ' ') { 
                freq[str[i] - 'a']++; 
            } 
        } 
   
        // for each character, where character is obtained by 
        // (i + 'a') check whether it is the maximum character 
        // so far and accordingly update 'result' 
        for (int i = 0; i < 26; i++) { 
            if (max < freq[i]) { 
                max = freq[i]; 
                result = (char) (i + 'a'); 
            } 
        } 
   
        // maximum occurring character 
        return result; 
    } 
   
// Driver Code 
    public static void Main() { 
        string str = "sample program"; 
        Console.WriteLine("Maximum occurring character = "
                + getMaxOccurringChar(str)); 
    } 
}  
  

Output

Maximum occurring character = a

complexity Analysis:

Time Complexity: O(n), where n is the length of the given input string.
Auxiliary Space: O(1).

Source: Sabre Interview Experience | Set 2

Lexicographically smallest string after M operations

ayushjauhari14

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Maximum occurring lexicographically smallest character in a String

C++

Java

Python3

C#

Javascript

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