Extrae el valor numérico máximo de una string determinada | Conjunto 1 (enfoque general)

Dada una string alfanumérica, extraiga el valor numérico máximo de esa string. Los alfabetos solo estarán en minúsculas. 
Aquí se discute un enfoque para resolver el problema, otro usando expresiones regulares se da en el Conjunto 2 

Ejemplos: 

Input : 100klh564abc365bg
Output : 564
Maximum numeric value among 100, 564 
and 365 is 564.

Input : abchsd0sdhs
Output : 0

Su solución es simple, es decir, comience a atravesar la string y realice dos operaciones: 

  • 1) Si un valor numérico está presente en el índice actual, conviértalo en un número entero
 num = num*10 + (str[i]-'0') 
  • 2) De lo contrario, actualice el valor máximo y reinicie num = 0.

Devuelve el valor máximo en el último.

C++

// C++ program to extract the maximum value
#include<bits/stdc++.h>
using namespace std;
 
// Function to extract the maximum value
int extractMaximum(string str)
{
    int num = 0, res = 0;
 
    // Start traversing the given string
    for (int i = 0; i<str.length(); i++)
    {
        // If a numeric value comes, start converting
        // it into an integer till there are consecutive
        // numeric digits
        if (str[i] >= '0' && str[i] <= '9')
            num = num * 10 + (str[i]-'0');
 
        // Update maximum value
        else
        {
            res = max(res, num);
 
            // Reset the number
            num = 0;
        }
    }
 
    // Return maximum value
    return max(res, num);
}
 
// Driver program
int main()
{
    string str = "100klh564abc365bg";
    cout << extractMaximum(str);
    return 0;
}

Java

// Java program to extract the maximum value
 
class GFG
{
    // Method to extract the maximum value
    static int extractMaximum(String str)
    {
        int num = 0, res = 0;
      
        // Start traversing the given string
        for (int i = 0; i<str.length(); i++)
        {
            // If a numeric value comes, start converting
            // it into an integer till there are consecutive
            // numeric digits
            if (Character.isDigit(str.charAt(i)))
                num = num * 10 + (str.charAt(i)-'0');
      
            // Update maximum value
            else
            {
                res = Math.max(res, num);
      
                // Reset the number
                num = 0;
            }
        }
      
        // Return maximum value
        return Math.max(res, num);
    }
     
    // Driver method
    public static void main(String[] args)
    {
        String str = "100klh564abc365bg";
        System.out.println(extractMaximum(str));
    }   
}

Python3

# Python 3 program to extract
# the maximum value
def extractMaximum(ss):
    num, res = 0, 0
     
    # start traversing the given string
    for i in range(len(ss)):
         
        if ss[i] >= "0" and ss[i] <= "9":
            num = num * 10 + int(int(ss[i]) - 0)
        else:
            res = max(res, num)
            num = 0
         
    return max(res, num)
 
# Driver Code
ss = "100klh564abc365bg"
 
print(extractMaximum(ss))
 
# This code is contributed
# by mohit kumar 29

C#

// C# program to extract the maximum value
using System;
 
class GFG {
     
    // Method to extract the maximum value
    static int extractMaximum(String str)
    {
        int num = 0, res = 0;
     
        // Start traversing the given string
        for (int i = 0; i < str.Length; i++)
        {
             
            // If a numeric value comes, start
            // converting it into an integer
            // till there are consecutive
            // numeric digits
            if (char.IsDigit(str[i]))
                num = num * 10 + (str[i]-'0');
     
            // Update maximum value
            else
            {
                res = Math.Max(res, num);
     
                // Reset the number
                num = 0;
            }
        }
     
        // Return maximum value
        return Math.Max(res, num);
    }
     
    // Driver method
    public static void Main()
    {
        String str = "100klh564abc365bg";
         
        Console.Write(extractMaximum(str));
    }
}
 
// This code is contributed by nitin mittal.

PHP

<?php
// PHP program to extract the maximum value
 
// Function to extract the maximum value
function extractMaximum($str)
{
    $num = 0;
    $res = 0;
 
    // Start traversing the given string
    for ($i = 0; $i<strlen($str); $i++)
    {
         
        // If a numeric value comes,
        // start converting it into
        // an integer till there are
        // consecutive numeric digits
        if ($str[$i] >= '0' && $str[$i] <= '9')
            $num = $num * 10 + ($str[$i]-'0');
 
        // Update maximum value
        else
        {
            $res = max($res, $num);
 
            // Reset the number
            $num = 0;
        }
    }
 
    // Return maximum value
    return max($res, $num);
}
 
    // Driver Code
    $str = "100klh564abc365bg";
    echo extractMaximum($str);
 
// This code is contributed by nitin mittal.
?>

Javascript

<script>
 
// JavaScript program to extract
// the maximum value
 
// Method to extract the maximum value
function extractMaximum(str)
{
    var num = 0, res = 0;
  
    // Start traversing the given string
    for (i = 0; i<str.length; i++)
    {
        // If a numeric value comes,
        // start converting
        // it into an integer till
        // there are consecutive
        // numeric digits
        if (isDigit(str.charAt(i)))
            num = num * 10 +
            (str.charAt(i).charCodeAt(0)-
            '0'.charCodeAt(0));
  
        // Update maximum value
        else
        {
            res = Math.max(res, num);
  
            // Reset the number
            num = 0;
        }
    }
  
    // Return maximum value
    return Math.max(res, num);
}
 
function isDigit(c) {
      return c >= '0' && c <= '9';
    }
     
// Driver method
var str = "100klh564abc365bg";
document.write(extractMaximum(str));
 
// This code is contributed by Amit Katiyar
 
</script>
Producción

564

Complejidad de tiempo: O(n) , donde n es el tamaño de la string dada str
Espacio auxiliar: O(1)

Pero en el caso de grandes números, el programa anterior no funcionaría debido al rango de enteros en C y C++. Entonces, para manejar el caso de números grandes, debemos tomar cada valor numérico como una string separada y luego encontrar el valor máximo.

 
1) Start traversing the given string.
   Continue traversing if there are any 
   leading zeroes or any lowercase character.
  b) Form a string of integer values.
  c) Update the maximum string.
    i) If the maximum string and current 
       string are having equal lengths then 
       on the basis of the first unmatched 
       value return maximum string.
    ii) If both are having different lengths 
        then return the string with greater 
        length.

2) Return maximum string.

C++

// C++ program for above implementation
#include<bits/stdc++.h>
using namespace std;
 
// Utility function to find maximum string
string maximumNum(string curr_num, string res)
{
    int len1 = curr_num.length();
    int len2 = res.length();
 
    // If both having equal lengths
    if (len1 == len2)
    {
        // Reach first unmatched character / value
        int i = 0;
        while (curr_num[i]== res[i])
            i++;
 
        // Return string with maximum value
        if (curr_num[i] < res[i])
            return res;
        else
            return curr_num;
    }
 
    // If different lengths
    // return string with maximum length
    return len1 < len2 ? res: curr_num;
}
 
// Function to extract the maximum value
string extractMaximum(string str)
{
    int n = str.length();
    string curr_num ="";
    string res;
 
    // Start traversing the string
    for (int i = 0; i<n; i++)
    {
        // Ignore leading zeroes
        while (i<n && str[i]=='0')
            i++;
 
        // Store numeric value into a string
        while (i<n && str[i]>='0' && str[i]<='9')
        {
            curr_num = curr_num + str[i];
            i++;
        }
 
        if (i == n)
            break;
 
        if (curr_num.size() > 0)
            i--;
 
        // Update maximum string
        res = maximumNum(curr_num, res);
 
        curr_num = "";
    }
 
    // To handle the case if there is only
    // 0 numeric value
    if (curr_num.size()== 0 && res.size()== 0)
        res = res + '0';
 
    // Return maximum string
    return maximumNum(curr_num, res);
}
 
// Drivers program
int main()
{
    string str ="100klh564abc365bg";
    cout << extractMaximum(str) << endl;
    return 0;
}

Java

// Java program for above implementation
 
class GFG
{
    // Utility method to find maximum string
    static String maximumNum(String curr_num, String res)
    {
        int len1 = curr_num.length();
        int len2 = res.length();
      
        // If both having equal lengths
        if (len1 == len2)
        {
            // Reach first unmatched character / value
            int i = 0;
            while (curr_num.charAt(i) == res.charAt(i))
                i++;
      
            // Return string with maximum value
            if (curr_num.charAt(i) < res.charAt(i))
                return res;
            else
                return curr_num;
        }
      
        // If different lengths
        // return string with maximum length
        return len1 < len2 ? res: curr_num;
    }
      
    // Method to extract the maximum value
    static String extractMaximum(String str)
    {
        int n = str.length();
        String curr_num ="";
        String res="";
      
        // Start traversing the string
        for (int i = 0; i<n; i++)
        {
            // Ignore leading zeroes
            while (i<n && str.charAt(i)=='0')
                i++;
      
            // Store numeric value into a string
            while (i<n && Character.isDigit(str.charAt(i)))
            {
                curr_num = curr_num + str.charAt(i);
                i++;
            }
      
            if (i == n)
                break;
      
            if (curr_num.length() > 0)
                i--;
      
            // Update maximum string
            res = maximumNum(curr_num, res);
      
            curr_num = "";
        }
      
        // To handle the case if there is only
        // 0 numeric value
        if (curr_num.length() == 0 && res.length() == 0)
            res = res + '0';
      
        // Return maximum string
        return maximumNum(curr_num, res);
    }
     
    // Driver method
    public static void main(String[] args)
    {
        String str = "100klh564abc365bg";
        System.out.println(extractMaximum(str));
    }   
}

Python3

# Python3 program for above implementation
 
# Utility function to find maximum string
def maximumNum(curr_num, res):
 
    len1 = len(curr_num);
    len2 = len(res);
 
    # If both having equal lengths
    if (len1 == len2):
         
        # Reach first unmatched character / value
        i = 0;
        while (curr_num[i]== res[i]):
            i += 1;
 
        # Return string with maximum value
        if (curr_num[i] < res[i]):
            return res;
        else:
            return curr_num;
 
    # If different lengths
    # return string with maximum length
    return res if(len1 < len2) else curr_num;
 
# Function to extract the maximum value
def extractMaximum(str):
 
    n = len(str);
    curr_num = "";
    res = "";
 
    # Start traversing the string
    for i in range(n):
         
        # Ignore leading zeroes
        while (i < n and str[i]=='0'):
            i += 1;
 
        # Store numeric value into a string
        while (i < n and str[i] >= '0' and
                         str[i] <= '9'):
            curr_num += str[i];
            i += 1;
 
        if (i == n):
            break;
 
        if (len(curr_num) > 0):
            i -= 1;
 
        # Update maximum string
        res = maximumNum(curr_num, res);
 
        curr_num = "";
 
    # To handle the case if there is only
    # 0 numeric value
    if (len(curr_num) == 0 and len(res) == 0):
        res += '0';
 
    # Return maximum string
    return maximumNum(curr_num, res);
 
# Driver Code
str ="100klh564abc365bg";
print(extractMaximum(str));
     
# This code is contributed by mits

C#

// C# program for above implementation
using System;
class GFG
{
    // Utility method to find maximum string
    static String maximumNum(string curr_num, string res)
    {
        int len1 = curr_num.Length;
        int len2 = res.Length;
     
        // If both having equal lengths
        if (len1 == len2)
        {
            // Reach first unmatched character / value
            int i = 0;
            while (curr_num[i] == res[i])
                i++;
     
            // Return string with maximum value
            if (curr_num[i] < res[i])
                return res;
            else
                return curr_num;
        }
     
        // If different lengths
        // return string with maximum length
        return len1 < len2 ? res: curr_num;
    }
     
    // Method to extract the maximum value
    static string extractMaximum(string str)
    {
        int n = str.Length;
        string curr_num ="";
        string res="";
     
        // Start traversing the string
        for (int i = 0; i<n; i++)
        {
            // Ignore leading zeroes
            while (i<n && str[i]=='0')
                i++;
     
            // Store numeric value into a string
            while (i<n && Char.IsDigit(str[i]))
            {
                curr_num = curr_num + str[i];
                i++;
            }
     
            if (i == n)
                break;
     
            if (curr_num.Length > 0)
                i--;
     
            // Update maximum string
            res = maximumNum(curr_num, res);
     
            curr_num = "";
        }
     
        // To handle the case if there is only
        // 0 numeric value
        if (curr_num.Length == 0 && res.Length == 0)
            res = res + '0';
     
        // Return maximum string
        return maximumNum(curr_num, res);
    }
     
    // Driver method
    public static void Main()
    {
        string str = "100klh564abc365bg";
        Console.WriteLine(extractMaximum(str));
    }    
}
// This code is contributed by mits

PHP

<?php
// PHP program for above implementation
 
// Utility function to find maximum string
function maximumNum($curr_num, $res)
{
    $len1 = strlen($curr_num);
    $len2 = strlen($res);
 
    // If both having equal lengths
    if ($len1 == $len2)
    {
        // Reach first unmatched character / value
        $i = 0;
        while ($curr_num[$i]== $res[$i])
            $i++;
 
        // Return string with maximum value
        if ($curr_num[$i] < $res[$i])
            return $res;
        else
            return $curr_num;
    }
 
    // If different lengths
    // return string with maximum length
    return $len1 < $len2 ? $res: $curr_num;
}
 
// Function to extract the maximum value
function extractMaximum($str)
{
    $n = strlen($str);
    $curr_num ="";
    $res="";
 
    // Start traversing the string
    for ($i = 0; $i<$n; $i++)
    {
        // Ignore leading zeroes
        while ($i<$n && $str[$i]=='0')
            $i++;
 
        // Store numeric value into a string
        while ($i<$n && $str[$i]>='0' && $str[$i]<='9')
        {
            $curr_num .= $str[$i];
            $i++;
        }
 
        if ($i == $n)
            break;
 
        if (strlen($curr_num) > 0)
            $i--;
 
        // Update maximum string
        $res = maximumNum($curr_num, $res);
 
        $curr_num = "";
    }
 
    // To handle the case if there is only
    // 0 numeric value
    if (strlen($curr_num)== 0 && strlen($res)== 0)
        $res .= '0';
 
    // Return maximum string
    return maximumNum($curr_num, $res);
}
 
// Drivers program
 
    $str ="100klh564abc365bg";
    echo extractMaximum($str);
     
// this code is contributed by mits
?>

Javascript

<script>
 
// JavaScript program for above implementation
 
     
    // Utility method to find maximum string
    function maximumNum(curr_num,res)
    {
        let len1 = curr_num.length;
        let len2 = res.length;
        
        // If both having equal lengths
        if (len1 == len2)
        {
            // Reach first unmatched character / value
            let i = 0;
            while (curr_num[i] == res[i])
                i++;
        
            // Return string with maximum value
            if (curr_num[i] < res[i])
                return res;
            else
                return curr_num;
        }
        
        // If different lengths
        // return string with maximum length
        return len1 < len2 ? res: curr_num;
    }
     
    // Method to extract the maximum value
    function extractMaximum(str)
    {
        let n = str.length;
        let curr_num ="";
        let res="";
        
        // Start traversing the string
        for (let i = 0; i<n; i++)
        {
            // Ignore leading zeroes
            while (i<n && str[i]=='0')
                i++;
        
            // Store numeric value into a string
            while (i<n && !isNaN(String(str[i]) * 1))
            {
                curr_num = curr_num + str[i];
                i++;
            }
        
            if (i == n)
                break;
        
            if (curr_num.length > 0)
                i--;
        
            // Update maximum string
            res = maximumNum(curr_num, res);
        
            curr_num = "";
        }
        
        // To handle the case if there is only
        // 0 numeric value
        if (curr_num.length == 0 && res.length == 0)
            res = res + '0';
        
        // Return maximum string
        return maximumNum(curr_num, res);
    }
     
    // Driver method
    let str = "100klh564abc365bg";
    document.write(extractMaximum(str));
     
 
// This code is contributed by unknown2108
 
</script>
Producción

564

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Artículo escrito por GeeksforGeeks-1 y traducido por Barcelona Geeks. The original can be accessed here. Licence: CCBY-SA

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