两个大写字母之间的最大不同小写字母

给定一个包含小写和大写字母的字符串，找出两个大写字母之间存在的不同小写字母的最大计数。
例子：

Input : zACaAbbaazzC
Output : The maximum count = 3

Input : edxedxxxCQiIVmYEUtLi
Output : The maximum count = 1

方法一（使用字符计数数组）：

• 声明一个大小为 26 的数组，其中数组的每个索引代表英文字母表中的一个字符
• 在整个长度上迭代字符串
• 对于每个小写字符，将相应数组的索引增加 1。
• 对于每个大写字符，迭代数组并计算值大于零的位置数。
• 如果此计数大于最大计数，则更新最大计数器，并将数组初始化为 0 。

下面是上述方法的实现。

C++

// CPP Program to find maximum
// lowercase alphabets present
// between two uppercase alphabets
#include 
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

= '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
?>

Javascript

// Javascript Program to find maximum
// lowercase alphabets present
// between two uppercase alphabets
     
    let MAX_CHAR = 26;
     
    // Function which computes the
    // maximum number of distinct
    // lowercase alphabets between
    // two uppercase alphabets
    function maxLower(str)
    {
        let n = str.length;
  
        // Ignoring lowercase characters in the
        // beginning.
        let 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.
        let maxCount = 0;
        let count = new Array(MAX_CHAR);
        for (; i < n; i++)
        {
  
            // If character is in uppercase,
            if (str[i] >= 'A' && str[i] <= 'Z')
            {
  
                // Count all distinct lower case
                // characters
                let currCount = 0;
                for (let j = 0; j < MAX_CHAR; j++)
                {
                    if (count[j] > 0)
                    {
                        currCount++;
                    }
                }
  
                // Update maximum count
                maxCount = Math.max(maxCount, currCount);
  
                // Reset count array
                for(let i=0;i<count.length;i++)
                {
                    count[i]=0;
                }
            }
  
            // If character is in lowercase
            if (str[i] >= 'a' && str[i] <= 'z')
            {
                count[str[i].charCodeAt(0) - 'a'.charCodeAt(0)]++;
            }
        }
        return maxCount;
    }
     
    // Driver code
    let str = "zACaAbbaazzC";
    document.write(maxLower(str));
 
     
     
    // This code is contributed by avanitrachhadiya2155

输出：

3

时间复杂度： O(n)。方法二（使用哈希表）：在该方法中，我们广泛使用了C++ STL容器unordered_set。
下面是上述方法的实现：

C++

// CPP Program to find maximum
// lowercase alphabets present
// between two uppercase alphabets
#include 
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 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 s = new HashSet();
    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

蟒蛇3

# 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 s = new HashSet();
    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

Javascript

// Javascript 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
function maxLower(str)
{
    let n = str.length;
  
    // Ignoring lowercase characters in the
    // beginning.
    let i = 0;
    for (; i < n; i++)
    {
        if (str[i].charCodeAt(0) >= 'A'.charCodeAt(0) && str[i].charCodeAt(0) <= 'Z'.charCodeAt(0))
        {
            i++;
            break;
        }
    }
  
    // We start from next of first capital letter
    // and traverse through remaining character.
    let maxCount = 0;
    let s = new Set();
    for (; i < n; i++)
    {
  
        // If character is in uppercase,
        if (str[i].charCodeAt(0) >= 'A'.charCodeAt(0) && str[i].charCodeAt(0) <= 'Z'.charCodeAt(0))
        {
  
            // Update maximum count if lowercase
            // character before this is more.
            maxCount = Math.max(maxCount, s.size);
  
            // clear the set
            s.clear();
        }
  
        // If character is in lowercase
        if (str[i].charCodeAt(0) >= 'a'.charCodeAt(0) && str[i].charCodeAt(0) <= 'z'.charCodeAt(0))
            s.add(str[i]);
    }
  
    return maxCount;
}
 
// Driver Code
let str = "zACaAbbaazzC";
document.write(maxLower(str.split("")));
     
    // This code is contributed by rag2127

输出：

3

时间复杂度： 0(n)

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