Maximum distinct lowercase alphabets between two uppercase

Difficulty Level : Easy
Last Updated : 02 Nov, 2020

Given a string containing alphabets in lowercase and uppercase, find the maximum count of distinct lowercase alphabets present between two uppercase alphabets.
Examples :

Input : zACaAbbaazzC
Output : The maximum count = 3

Input : edxedxxxCQiIVmYEUtLi
Output : The maximum count = 1

Method 1 (Using Character Count Array):

Declare an array of size 26 where each index of the array represents a character in the English alphabet
Iterate the string over its complete length
For each lowercase character, increment the index of the corresponding array by 1.
For each uppercase character, iterate the array and count the number of positions having value greater than zero.
If this count is greater than the maximum count, update the maximum counter, and initialize the array by 0.

Below is the implementation of the above method.

C++

// CPP Program to find maximum
// lowercase alphabets present
// between two uppercase alphabets
#include <bits/stdc++.h>
using namespace std;
 
#define MAX_CHAR 26
 
// Function which computes the
// maximum number of distinct
// lowercase alphabets between
// two uppercase alphabets
int maxLower(string str)
{
    int n = str.length();
 
    // Ignoring lowercase characters in the
    // beginning.
    int i = 0;
    for (; i < n; i++) {
        if (str[i] >= 'A' && str[i] <= 'Z') {
            i++;
            break;
        }
    }
 
    // We start from next of first capital letter
    // and traverse through remaining character.
    int maxCount = 0;
    int count[MAX_CHAR] = { 0 };
    for (; i < n; i++) {
 
        // If character is in uppercase,
        if (str[i] >= 'A' && str[i] <= 'Z') {
 
            // Count all distinct lower case
            // characters
            int currCount = 0;
            for (int j = 0; j < MAX_CHAR; j++)
                if (count[j] > 0)
                    currCount++;
 
            // Update maximum count
            maxCount = max(maxCount, currCount);
 
            // Reset count array
            memset(count, 0, sizeof(count));
        }
 
        // If character is in lowercase
        if (str[i] >= 'a' && str[i] <= 'z')
            count[str[i] - 'a']++;
    }
 
    return maxCount;
}
 
// Driver function
int main()
{
    string str = "zACaAbbaazzC";
    cout << maxLower(str);
    return 0;
}

Java

// Java Program to find maximum
// lowercase alphabets present
// between two uppercase alphabets
import java.util.Arrays;
 
class GFG 
{
 
    static final int MAX_CHAR = 26;
 
    // Function which computes the
    // maximum number of distinct
    // lowercase alphabets between
    // two uppercase alphabets
    static int maxLower(String str) 
    {
        int n = str.length();
 
        // Ignoring lowercase characters in the
        // beginning.
        int i = 0;
        for (; i < n; i++)
        {
            if (str.charAt(i) >= 'A' && str.charAt(i) <= 'Z')
            {
                i++;
                break;
            }
        }
 
        // We start from next of first capital letter
        // and traverse through remaining character.
        int maxCount = 0;
        int count[] = new int[MAX_CHAR];
        for (; i < n; i++) 
        {
 
            // If character is in uppercase,
            if (str.charAt(i) >= 'A' && str.charAt(i) <= 'Z') 
            {
 
                // Count all distinct lower case
                // characters
                int currCount = 0;
                for (int j = 0; j < MAX_CHAR; j++) 
                {
                    if (count[j] > 0) 
                    {
                        currCount++;
                    }
                }
 
                // Update maximum count
                maxCount = Math.max(maxCount, currCount);
 
                // Reset count array
                Arrays.fill(count, 0);
            }
 
            // If character is in lowercase
            if (str.charAt(i) >= 'a' && str.charAt(i) <= 'z')
            {
                count[str.charAt(i) - 'a']++;
            }
        }
        return maxCount;
    }
 
    // Driver code
    public static void main(String[] args) 
    {
        String str = "zACaAbbaazzC";
        System.out.println(maxLower(str));
    }
}
 
// This code is contributed by Rajput-Ji

Python3

# Python3 Program to find maximum
# lowercase alphabets present
# between two uppercase alphabets
 
MAX_CHAR = 26
 
# Function which computes the
# maximum number of distinct
# lowercase alphabets between
# two uppercase alphabets
def maxLower(str):
    n = len(str)
 
    # Ignoring lowercase characters 
    # in the beginning.
    i = 0
    for i in range(n):
        if str[i] >= 'A' and str[i] <= 'Z':
            i += 1
            break
             
    # We start from next of first capital 
    # letter and traverse through 
    # remaining character.
    maxCount = 0
    count = []
    for j in range(MAX_CHAR):
        count.append(0)
         
    for j in range(i, n):
 
        # If character is in uppercase,
        if str[j] >= 'A' and str[j] <= 'Z':
 
            # Count all distinct lower
            # case characters
            currCount = 0
            for k in range(MAX_CHAR):
                if count[k] > 0:
                    currCount += 1
 
            # Update maximum count
            maxCount = max(maxCount, currCount)
 
            # Reset count array
            for y in count:
                y = 0
                 
        # If character is in lowercase
        if str[j] >= 'a' and str[j] <= 'z':
            count[ord(str[j]) - ord('a')] += 1
             
    return maxCount
 
# Driver function
str = "zACaAbbaazzC";
print(maxLower(str))
 
# This code is contributed by Upendra Bartwal

C#

// C# Program to find maximum
// lowercase alphabets present
// between two uppercase alphabets
using System;
using System.Collections.Generic;             
 
class GFG 
{
    static int MAX_CHAR = 26;
 
    // Function which computes the
    // maximum number of distinct
    // lowercase alphabets between
    // two uppercase alphabets
    static int maxLower(String str) 
    {
        int n = str.Length;
 
        // Ignoring lowercase characters in the
        // beginning.
        int i = 0;
        for (; i < n; i++)
        {
            if (str[i] >= 'A' && str[i] <= 'Z')
            {
                i++;
                break;
            }
        }
 
        // We start from next of first capital letter
        // and traverse through remaining character.
        int maxCount = 0;
        int []count = new int[MAX_CHAR];
        for (; i < n; i++) 
        {
 
            // If character is in uppercase,
            if (str[i] >= 'A' && str[i] <= 'Z') 
            {
 
                // Count all distinct lower case
                // characters
                int currCount = 0;
                for (int j = 0; j < MAX_CHAR; j++) 
                {
                    if (count[j] > 0) 
                    {
                        currCount++;
                    }
                }
 
                // Update maximum count
                maxCount = Math.Max(maxCount, currCount);
 
                // Reset count array
                Array.Fill(count, 0);
            }
 
            // If character is in lowercase
            if (str[i] >= 'a' && str[i] <= 'z')
            {
                count[str[i] - 'a']++;
            }
        }
        return maxCount;
    }
 
    // Driver code
    public static void Main(String[] args) 
    {
        String str = "zACaAbbaazzC";
        Console.WriteLine(maxLower(str));
    }
}
 
// This code is contributed by PrinciRaj1992

PHP

<?php 
// PHP Program to find maximum
// lowercase alphabets present
// between two uppercase alphabets
$MAX_CHAR = 26;
 
// Function which computes the
// maximum number of distinct
// lowercase alphabets between
// two uppercase alphabets
function maxLower($str)
{
    global $MAX_CHAR;
    $n = strlen($str);
 
    // Ignoring lowercase characters in 
    // the beginning.
    $i = 0;
    for (; $i < $n; $i++) 
    {
        if ($str[$i] >= 'A' && 
            $str[$i] <= 'Z')
        {
            $i++;
            break;
        }
    }
 
    // We start from next of first capital letter
    // and traverse through remaining character.
    $maxCount = 0;
    $count = array_fill(0, $MAX_CHAR, NULL);
    for (; $i < $n; $i++) 
    {
 
        // If character is in uppercase,
        if ($str[$i] >= 'A' && $str[$i] <= 'Z') 
        {
 
            // Count all distinct lower case
            // characters
            $currCount = 0;
            for ($j = 0; $j < $MAX_CHAR; $j++)
                if ($count[$j] > 0)
                    $currCount++;
 
            // Update maximum count
            $maxCount = max($maxCount, $currCount);
 
            // Reset count array
            $count = array_fill(0, $MAX_CHAR, NULL);
        }
 
        // If character is in lowercase
        if ($str[$i] >= 'a' && $str[$i] <= 'z')
            $count[ord($str[$i]) - ord('a')]++;
    }
 
    return $maxCount;
}
 
// Driver Code
$str = "zACaAbbaazzC";
echo maxLower($str);
 
// This code is contributed by ita_c
?>

Output:

Time Complexity: O(n).

Method 2 (Using Hash Table): In this method, we extensively use the C++ STL container unordered_set.
Below is the implementation of the above method :

C++

// CPP Program to find maximum
// lowercase alphabets present
// between two uppercase alphabets
#include <bits/stdc++.h>
using namespace std;
 
// Function which computes the
// maximum number of distinct
// lowercase alphabets between
// two uppercase alphabets
int maxLower(string str)
{
    int n = str.length();
 
    // Ignoring lowercase characters in the
    // beginning.
    int i = 0;
    for (; i < n; i++) {
        if (str[i] >= 'A' && str[i] <= 'Z') {
            i++;
            break;
        }
    }
 
    // We start from next of first capital letter
    // and traverse through remaining character.
    int maxCount = 0;
    unordered_set<int> s;
    for (; i < n; i++) {
 
        // If character is in uppercase,
        if (str[i] >= 'A' && str[i] <= 'Z') {
 
            // Update maximum count if lowercase
            // character before this is more.
            maxCount = max(maxCount, (int)s.size());
 
            // clear the set
            s.clear();
        }
 
        // If character is in lowercase
        if (str[i] >= 'a' && str[i] <= 'z')
            s.insert(str[i]);
    }
 
    return maxCount;
}
 
// Driver function
int main()
{
    string str = "zACaAbbaazzC";
    cout << maxLower(str);
    return 0;
}

Java

// Java Program to find maximum
// lowercase alphabets present
// between two uppercase alphabets
import java.util.*;
 
class GFG 
{
 
// Function which computes the
// maximum number of distinct
// lowercase alphabets between
// two uppercase alphabets
static int maxLower(char[] str)
{
    int n = str.length;
 
    // Ignoring lowercase characters in the
    // beginning.
    int i = 0;
    for (; i < n; i++)
    {
        if (str[i] >= 'A' && str[i] <= 'Z') 
        {
            i++;
            break;
        }
    }
 
    // We start from next of first capital letter
    // and traverse through remaining character.
    int maxCount = 0;
    HashSet<Integer> s = new HashSet<Integer>();
    for (; i < n; i++) 
    {
 
        // If character is in uppercase,
        if (str[i] >= 'A' && str[i] <= 'Z') 
        {
 
            // Update maximum count if lowercase
            // character before this is more.
            maxCount = Math.max(maxCount, (int)s.size());
 
            // clear the set
            s.clear();
        }
 
        // If character is in lowercase
        if (str[i] >= 'a' && str[i] <= 'z')
            s.add((int)str[i]);
    }
 
    return maxCount;
}
 
// Driver Code
public static void main(String args[]) 
{
    String str = "zACaAbbaazzC";
    System.out.println(maxLower(str.toCharArray()));
}
}
 
// This code is contributed by PrinciRaj1992

Python3

# Python3 Program to find maximum
# lowercase alphabets present
# between two uppercase alphabets
 
# Function which computes the
# maximum number of distinct
# lowercase alphabets between
# two uppercase alphabets
def maxLower(str):
   
    n = len(str);
 
    # Ignoring lowercase characters 
    # in the beginning.
    i = 0;
    for i in range(n):
       
        if (str[i] >= 'A' and
            str[i] <= 'Z'):
            i += 1;
            break;
 
    # We start from next of first 
    # capital letter and traverse 
    # through remaining character.
    maxCount = 3;
    s = set()
     
    for i in range(n):
 
        # If character is in 
        # uppercase,
        if (str[i] >= 'A' and
            str[i] <= 'Z'):
           
            # Update maximum count if 
            # lowercase character before 
            # this is more.
            maxCount = max(maxCount, 
                           len(s));
             
            # clear the set
            s.clear();
 
        # If character is in
        # lowercase
        if (str[i] >= 'a' and
            str[i] <= 'z'):
            s.add(str[i]);
            return maxCount;
 
# Driver Code
if __name__ == '__main__':
   
    str = "zACaAbbaazzC";
    print(maxLower(str));
 
# This code is contributed by 29AjayKumar

C#

// C# Program to find maximum
// lowercase alphabets present
// between two uppercase alphabets
using System;
using System.Collections.Generic; 
 
class GFG 
{
 
// Function which computes the
// maximum number of distinct
// lowercase alphabets between
// two uppercase alphabets
static int maxLower(char[] str)
{
    int n = str.Length;
 
    // Ignoring lowercase characters in the
    // beginning.
    int i = 0;
    for (; i < n; i++)
    {
        if (str[i] >= 'A' && str[i] <= 'Z') 
        {
            i++;
            break;
        }
    }
 
    // We start from next of first capital letter
    // and traverse through remaining character.
    int maxCount = 0;
    HashSet<int> s = new HashSet<int>();
    for (; i < n; i++) 
    {
 
        // If character is in uppercase,
        if (str[i] >= 'A' && str[i] <= 'Z') 
        {
 
            // Update maximum count if lowercase
            // character before this is more.
            maxCount = Math.Max(maxCount,
                           (int)s.Count);
 
            // clear the set
            s.Clear();
        }
 
        // If character is in lowercase
        if (str[i] >= 'a' && str[i] <= 'z')
            s.Add((int)str[i]);
    }
 
    return maxCount;
}
 
// Driver Code
public static void Main(String []args) 
{
    String str = "zACaAbbaazzC";
    Console.WriteLine(maxLower(str.ToCharArray()));
}
}
 
// This code is contributed by Rajput-Ji

Output:

Time complexity : 0(n)

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