Program to find Smallest and Largest Word in a String

Given a string, find the minimum and the maximum length words in it. 

Examples:

Input : "This is a test string"
Output : Minimum length word: a
         Maximum length word: string
Input : "GeeksforGeeks A computer Science portal for Geeks"
Output : Minimum length word: A
         Maximum length word: GeeksforGeeks

Method 1:

The idea is to keep a starting index si and an ending index ei. 

• si points to the starting of a new word and we traverse the string using ei.
• Whenever a space or ‘\0’ character is encountered,we compute the length of the current word using (ei – si) and compare it with the minimum and the maximum length so far. 
  
  • If it is less, update the min_length and the min_start_index( which points to the starting of the minimum length word).
  • If it is greater, update the max_length and the max_start_index( which points to the starting of the maximum length word).
• Finally, update minWord and maxWord which are output strings that have been sent by reference with the substrings starting at min_start_index and max_start_index of length min_length and max_length respectively.

Below is the implementation of the above approach:

C++

// CPP Program to find Smallest and 
// Largest Word in a String
#include<iostream>
#include<cstring>
using namespace std;

void minMaxLengthWords(string input, string &minWord, string &maxWord) 
{
    // minWord and maxWord are received by reference 
    // and not by value
    // will be used to store and return output
    int len = input.length();
    int si = 0, ei = 0;
  
  
    int min_length = len, min_start_index = 0, max_length = 0, max_start_index = 0;

    // Loop while input string is not empty
    while (ei <= len) 
    {
        if (ei < len && input[ei] != ' ')
            ei++;
        
        else 
        {
            // end of a word
            // find curr word length
            int curr_length = ei - si;
        
            if (curr_length < min_length) 
            {
                min_length = curr_length;
                min_start_index = si;
            }
            
            if (curr_length > max_length)
            {
                max_length = curr_length;
                max_start_index = si;
            }
            ei++;
            si = ei;
        }
    }
    
    // store minimum and maximum length words
    minWord = input.substr(min_start_index, min_length);
    maxWord = input.substr(max_start_index, max_length); 
}

// Driver code
int main() 
{
    string a = "GeeksforGeeks A Computer Science portal for Geeks";
    string minWord, maxWord;
    minMaxLengthWords(a, minWord, maxWord);
    
    // to take input in string use getline(cin, a);
    cout << "Minimum length word: "
        << minWord << endl
        << "Maximum length word: "
        << maxWord << endl;
} 

Java

// Java Program to find Smallest and 
// Largest Word in a String
import java.io.*;
class GFG
{

    static String minWord = "", maxWord = "";

    static void minMaxLengthWords(String input) 
    {
          input=input.trim();//Triming any space before the String else space at start would be consider as smallest word      
        // minWord and maxWord are received by reference 
        // and not by value
        // will be used to store and return output
        
        int len = input.length();
        int si = 0, ei = 0;
        int min_length = len, min_start_index = 0,
              max_length = 0, max_start_index = 0;

        // Loop while input string is not empty
        while (ei <= len) 
        {
            if (ei < len && input.charAt(ei) != ' ')
            {
                ei++;
            } 
            else
            {
                // end of a word
                // find curr word length
                int curr_length = ei - si;

                if (curr_length < min_length) 
                {
                    min_length = curr_length;
                    min_start_index = si;
                }

                if (curr_length > max_length) 
                {
                    max_length = curr_length;
                    max_start_index = si;
                }
                ei++;
                si = ei;
            }
        }

        // store minimum and maximum length words
        minWord = input.substring(min_start_index, min_start_index + min_length);
        maxWord = input.substring(max_start_index, max_start_index+max_length);//Earlier  code was not working if the largests word is inbetween String
    }

    // Driver code
    public static void main(String[] args)
    {
        String a = "GeeksforGeeks A Computer Science portal for Geeks";

        minMaxLengthWords(a);

        // to take input in string use getline(cin, a);
        System.out.print("Minimum length word: "
                + minWord
                + "\nMaximum length word: "
                + maxWord);
    }
}

// This code contributed by Rajput-Ji

Python 3

# Python3 program to find Smallest and 
# Largest Word in a String

# defining the method to find the longest 
# word and the shortest word
def minMaxLengthWords(inp):
    length = len(inp)
    si = ei = 0
    min_length = length
    min_start_index = max_length = max_start_index = 0
    
    # loop to find the length and stating index
    # of both longest and shortest words
    while ei <= length:
        if (ei < length) and (inp[ei] != " "):
            ei += 1
        else:
            curr_length = ei - si
            
            # condition checking for the shortest word
            if curr_length < min_length:
                min_length = curr_length
                min_start_index = si
                
            # condition for the longest word 
            if curr_length > max_length:
                max_length = curr_length
                max_start_index = si
            ei += 1
            si = ei
            
    # extracting the shortest word using 
    # it's starting index and length     
    minWord = inp[min_start_index : 
                  min_start_index + min_length]
    
    # extracting the longest word using 
    # it's starting index and length     
    maxWord = inp[max_start_index : max_length]
    
    # printing the final result
    print("Minimum length word: ", minWord)
    print ("Maximum length word: ", maxWord)
    
# Driver Code

# Using this string to test our code
a = "GeeksforGeeks A Computer Science portal for Geeks"
minMaxLengthWords(a)

# This code is contributed by Animesh_Gupta

C#

// C# Program to find Smallest and 
// Largest Word in a String
using System;

class GFG
{

    static String minWord = "", maxWord = "";

    static void minMaxLengthWords(String input) 
    {
        // minWord and maxWord are received by reference 
        // and not by value
        // will be used to store and return output
        int len = input.Length;
        int si = 0, ei = 0;
        int min_length = len, min_start_index = 0,
            max_length = 0, max_start_index = 0;

        // Loop while input string is not empty
        while (ei <= len) 
        {
            if (ei < len && input[ei] != ' ')
            {
                ei++;
            } 
            else
            {
                // end of a word
                // find curr word length
                int curr_length = ei - si;

                if (curr_length < min_length) 
                {
                    min_length = curr_length;
                    min_start_index = si;
                }

                if (curr_length > max_length) 
                {
                    max_length = curr_length;
                    max_start_index = si;
                }
                ei++;
                si = ei;
            }
        }

        // store minimum and maximum length words
        minWord = input.Substring(min_start_index, min_length);
        maxWord = input.Substring(max_start_index, max_length);
    }

    // Driver code
    public static void Main(String[] args)
    {
        String a = "GeeksforGeeks A Computer Science portal for Geeks";

        minMaxLengthWords(a);

        // to take input in string use getline(cin, a);
        Console.Write("Minimum length word: "
                + minWord
                + "\nMaximum length word: "
                + maxWord);
    }
}

// This code has been contributed by 29AjayKumar

Javascript

<script>

// JavaScript Program to find Smallest and 
// Largest Word in a String

let minWord = "";
let maxWord = "";

function minMaxLengthWords(input) 
{
    // minWord and maxWord are received by reference 
    // and not by value
    // will be used to store and return output
    let len = input.length;
    let si = 0, ei = 0;
    let min_length = len;
    let min_start_index = 0;
    let max_length = 0;
    let max_start_index = 0;

    // Loop while input string is not empty
    while (ei <= len) 
    {
        if (ei < len && input[ei] != ' ')
        {
            ei++;
        } 
        else
        {
            // end of a word
            // find curr word length
            let curr_length = ei - si;

            if (curr_length < min_length) 
            {
                min_length = curr_length;
                min_start_index = si;
            }

            if (curr_length > max_length) 
            {
                max_length = curr_length;
                max_start_index = si;
            }
            ei++;
            si = ei;
        }
    }

    // store minimum and maximum length words
    minWord = 
    input.substring(min_start_index,min_start_index + min_length);
    
    maxWord = 
    input.substring(max_start_index, max_length);
    
}

// Driver code

let a = "GeeksforGeeks A Computer Science portal for Geeks";

minMaxLengthWords(a);

// to take input in string use getline(cin, a);
document.write("Minimum length word: "
        + minWord+"<br>"
        + "Maximum length word:  "
        + maxWord);

</script>

Output

Minimum length word: A
Maximum length word: GeeksforGeeks

Time Complexity: O(n), where n is the length of string.
Auxiliary Space: O(n), where n is the length of string. This is because when string is passed in the function it creates a copy of itself in stack.

Method 2: By Using Regular Expressions

In this approach we uses regular expressions to find words in a given input string and iterates through them. It keeps track of the smallest and largest words based on their lengths and prints them.

• First, Define a regular expression pattern to match words.
• Then, Create iterators to search for words within the input string.
• Initialize variables to store the smallest and largest words.
• Iterate through the words in the string.
• Check if the current word is smaller than the smallest word.
• Check if the current word is larger than the largest word .
• At the end ,print the smallest and largest words.

C++

#include <iostream>
#include <string>
#include <regex>
#include <iterator>

// Function to find the smallest and largest words in a string using regular expressions
void findSmallestLargestWordsRegex(const std::string& input) {
    // Define a regular expression pattern to match words
    std::regex wordRegex("\\b\\w+\\b");

    // Create iterators to search for words within the input string
    std::sregex_iterator wordsBegin(input.begin(), input.end(), wordRegex);
    std::sregex_iterator wordsEnd;

    // Initialize variables to store the smallest and largest words
    std::string smallestWord, largestWord;

    // Iterate through the words in the string
    for (std::sregex_iterator it = wordsBegin; it != wordsEnd; ++it) {
        std::smatch match = *it;
        std::string word = match.str();

        // Check if the current word is smaller than the smallest word found so far
        if (word.length() < smallestWord.length() || smallestWord.empty()) {
            smallestWord = word;
        }

        // Check if the current word is larger than the largest word found so far
        if (word.length() > largestWord.length()) {
            largestWord = word;
        }
    }

    // Print the smallest and largest words
    std::cout << "Minimum length word: " << smallestWord << std::endl;
    std::cout << "Maximum length word: " << largestWord << std::endl;
}

int main() {
    // Input string
    std::string input = "This is a test string";

    // Call the function to find and display the smallest and largest words
    findSmallestLargestWordsRegex(input);

    return 0;
}
// Siddhesh 

Java

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class SmallestLargestWords {
    // Function to find the smallest and largest words in a string using regular expressions
    public static void findSmallestLargestWordsRegex(String input) {
        // Define a regular expression pattern to match words
        String wordRegex = "\\b\\w+\\b";
        Pattern pattern = Pattern.compile(wordRegex);
        Matcher matcher = pattern.matcher(input);

        // Initialize variables to store the smallest and largest words
        String smallestWord = "";
        String largestWord = "";

        // Iterate through the words in the string
        while (matcher.find()) {
            String word = matcher.group();

            // Check if the current word is smaller than the smallest word found so far
            if (word.length() < smallestWord.length() || smallestWord.isEmpty()) {
                smallestWord = word;
            }

            // Check if the current word is larger than the largest word found so far
            if (word.length() > largestWord.length()) {
                largestWord = word;
            }
        }

        // Print the smallest and largest words
        System.out.println("Minimum length word: " + smallestWord);
        System.out.println("Maximum length word: " + largestWord);
    }

    public static void main(String[] args) {
        // Input string
        String input = "This is a test string";

        // Call the function to find and display the smallest and largest words
        findSmallestLargestWordsRegex(input);
    }
}
// Siddhesh 

Python3

import re

# Function to find the smallest and largest words in a string using regular expressions
def find_smallest_largest_words_regex(input_str):
    # Define a regular expression pattern to match words
    word_regex = r'\b\w+\b'
    words = re.findall(word_regex, input_str)

    # Initialize variables to store the smallest and largest words
    smallest_word = ""
    largest_word = ""

    # Iterate through the words in the string
    for word in words:
        # Check if the current word is smaller than the smallest word found so far
        if len(word) < len(smallest_word) or not smallest_word:
            smallest_word = word

        # Check if the current word is larger than the largest word found so far
        if len(word) > len(largest_word):
            largest_word = word

    # Print the smallest and largest words
    print("Minimum length word:", smallest_word)
    print("Maximum length word:", largest_word)

# Input string
input_str = "This is a test string"

# Call the function to find and display the smallest and largest words
find_smallest_largest_words_regex(input_str)

# Siddhesh

C#

using System;
using System.Text.RegularExpressions;

class Program
{
    // Function to find the smallest and largest words in a string using regular expressions
    static void FindSmallestLargestWordsRegex(string input)
    {
        // Define a regular expression pattern to match words
        string wordPattern = @"\b\w+\b";

        // Use Regex.Matches to get a collection of words
        MatchCollection words = Regex.Matches(input, wordPattern);

        // Initialize variables to store the smallest and largest words
        string smallestWord = null, largestWord = null;

        // Iterate through the words in the collection
        foreach (Match match in words)
        {
            string word = match.Value;

            // Check if the current word is smaller than the smallest word found so far
            if (string.IsNullOrEmpty(smallestWord) || word.Length < smallestWord.Length)
            {
                smallestWord = word;
            }

            // Check if the current word is larger than the largest word found so far
            if (string.IsNullOrEmpty(largestWord) || word.Length > largestWord.Length)
            {
                largestWord = word;
            }
        }

        // Print the smallest and largest words
        Console.WriteLine("Minimum length word: " + smallestWord);
        Console.WriteLine("Maximum length word: " + largestWord);
    }

    static void Main()
    {
        // Input string
        string input = "This is a test string";

        // Call the function to find and display the smallest and largest words
        FindSmallestLargestWordsRegex(input);
    }
}

// This code is contributed by shivamgupta310570

Javascript

// Function to find the smallest and largest words in a string using regular expressions
function findSmallestLargestWordsRegex(input) {
    // Define a regular expression pattern to match words
    const wordRegex = /\b\w+\b/g;

    // Create an array of words by matching the regular expression
    const words = input.match(wordRegex) || [];

    // Initialize variables to store the smallest and largest words
    let smallestWord = '', largestWord = '';

    // Iterate through the words in the array
    for (const word of words) {
        // Check if the current word is smaller than the smallest word found so far
        if (word.length < smallestWord.length || smallestWord.length === 0) {
            smallestWord = word;
        }

        // Check if the current word is larger than the largest word found so far
        if (word.length > largestWord.length) {
            largestWord = word;
        }
    }

    // Print the smallest and largest words
    console.log("Minimum length word:", smallestWord);
    console.log("Maximum length word:", largestWord);
}

// Input string
const input = "This is a test string";

// Call the function to find and display the smallest and largest words
findSmallestLargestWordsRegex(input);

// This code is contributed by shivamgupta0987654321

Output

Minimum length word: a
Maximum length word: string

Time complexity: O(n), n is length of string
Space complexity: O(m), m is the length of the longest word.

Method 3: Using Stack

In this approach, we will push all the words one by one into a char stack and check for the max as well as min length for every word on the basis of that we will print the Minimum length word and Maximum length word.

Below is the implementation of the above approach:

C++

// CPP program to find Smallest and Largest Word in a String
// using stack
#include <bits/stdc++.h>
using namespace std;

pair<string, string> smallestAndLargestWord(string& str)
{
    // Pair to store the smallest and largest words
    pair<string, string> stringPair;
    // Stack to temporarily store characters of a word
    stack<char> stk;
    int n = str.size();
    // Variables to store the smallest and largest words
    string minWord = "";
    string maxWord = "";
    // Temporary variable to store each word
    string temp = "";

    // Loop through the characters of the string
    for (int i = 0; i < n; i++) {
        if (str[i] != ' ') {
            // Push characters onto the stack until a space
            // is encountered
            stk.push(str[i]);
        }
        else {
            // When a space is encountered, extract the word
            // from the stack
            while (!stk.empty()) {
                temp += stk.top();
                stk.pop();
            }

            // Compare the length of the current word with
            // the smallest and largest words found so far
            if (minWord == ""
                || temp.size() < minWord.size()) {
                minWord = temp;
            }

            if (maxWord == ""
                || temp.size() > maxWord.size()) {
                maxWord = temp;
            }

            // Reset the temporary variable for the next
            // word
            temp = "";
        }
    }

    // Extract the last word from the stack
    while (!stk.empty()) {
        temp += stk.top();
        stk.pop();
    }

    // Compare the length of the last word with the smallest
    // and largest words found so far
    if (minWord == "" || temp.size() < minWord.size()) {
        minWord = temp;
    }

    if (maxWord == "" || temp.size() > maxWord.size()) {
        maxWord = temp;
    }

    // Reverse both the strings as stack reverses them
    // already
    reverse(minWord.begin(), minWord.end());
    reverse(maxWord.begin(), maxWord.end());

    // Store the smallest and largest words in the pair
    stringPair.first = minWord;
    stringPair.second = maxWord;

    return stringPair;
}

int main()
{
    string str = "GeeksforGeeks A computer Science portal "
                 "for Geeks";
    // Call the function to find the smallest and largest
    // words
    pair<string, string> stringPair
        = smallestAndLargestWord(str);
    // Print the results
    cout << "Minimum length word: " << stringPair.first
         << endl;
    cout << "Maximum length word: " << stringPair.second
         << endl;

    return 0;
}

Output

Minimum length word: A
Maximum length word: GeeksforGeeks

Time complexity: O(n), n is length of string.
Auxiliary Space: O(m), m is the length of the longest word.