Skip to content
Related Articles

Related Articles

Improve Article
Save Article
Like Article

Smallest string containing all unique characters from given array of strings

  • Last Updated : 07 Jan, 2022

Given an array of strings arr[], the task is to find the smallest string which contains all the characters of the given array of strings.

Examples: 

Input: arr[] = {“your”, “you”, “or”, “yo”}
Output: ruyo
Explanation: The string “ruyo” is the smallest string which contains all the characters that are used across all the strings of the given array. 

Input: arr[] = {“abm”, “bmt”, “cd”, “tca”}
Output: abctdm

Approach: This problem can be solved by using the Set Data Structure. Set has the capability to remove duplicates, which is needed in this problem in order to minimize the string size. Add all the characters in the set from all the strings in the array arr[] and form a string containing all the characters remaining in the set, which is the required answer. 

Below is the implementation of the above approach.

C++




// C++ code for the above approach
#include <bits/stdc++.h>
using namespace std;
 
string minSubstr(vector<string> s)
{
   
    // Stores the concatenated string
    // of all the given strings
    string str = "";
 
    // Loop to iterate through all
    // the given strings
    for (int i = 0; i < s.size(); i++)
    {
        str += s[i];
    }
 
    // Set to store the characters
    unordered_set<char> set;
 
    // Loop to iterate over all
    // the characters in str
    for (int i = 0; i < str.length(); i++)
    {
        set.insert(str[i]);
    }
    string res = "";
   
    // Loop to iterate over the set
    for (auto itr = set.begin(); itr != set.end(); itr++)
    {
        res = res + (*itr);
    }
 
    // Return Answer
    return res;
}
 
// Driver Code
int main()
{
    vector<string> arr = {"your", "you",
                          "or", "yo"};
 
    cout << (minSubstr(arr));
    return 0;
}
 
// This code is contributed by Potta Lokesh

Java




import java.util.*;
 
public class GfG {
 
    public static String minSubstr(String s[])
    {
        // Stores the concatenated string
        // of all the given strings
        String str = "";
 
        // Loop to iterate through all
        // the given strings
        for (int i = 0; i < s.length; i++) {
            str += s[i];
        }
 
        // Set to store the characters
        Set<Character> set
            = new HashSet<Character>();
 
        // Loop to iterate over all
        // the characters in str
        for (int i = 0; i < str.length(); i++) {
            set.add(str.charAt(i));
        }
 
        // Stores the required answer
        String res = "";
        Iterator<Character> itr
            = set.iterator();
 
        // Loop to iterate over the set
        while (itr.hasNext()) {
            res += itr.next();
        }
 
        // Return Answer
        return res;
    }
 
    // Driver Code
    public static void main(String[] args)
    {
        String arr[]
            = new String[] { "your", "you",
                             "or", "yo" };
 
        System.out.println(minSubstr(arr));
    }
}

Python3




# Python code for the above approach
def minSubstr(s):
 
    # Stores the concatenated string
    # of all the given strings
    str = ""
 
    # Loop to iterate through all
    # the given strings
    for i in range(len(s)):
        str += s[i]
 
    # Set to store the characters
    _set = set()
 
    # Loop to iterate over all
    # the characters in str
    for i in range(len(str)):
        _set.add(str[i])
 
    # Stores the required answer
    res = ""
 
    # Loop to iterate over the set
    for itr in _set:
        res += itr
 
    # Return Answer
    return res
 
# Driver Code
arr = ["your", "you", "or", "yo"]
print(minSubstr(arr))
 
# This code is contributed by gfgking

C#




// C# program for the above approach
using System;
using System.Collections.Generic;
 
class GFG
{
    public static string minSubstr(string []s)
    {
        // Stores the concatenated string
        // of all the given strings
        string str = "";
 
        // Loop to iterate through all
        // the given strings
        for (int i = 0; i < s.Length; i++) {
            str += s[i];
        }
 
        // Set to store the characters
        HashSet<char> set = new HashSet<char>();
 
        // Loop to iterate over all
        // the characters in str
        for (int i = 0; i < str.Length; i++) {
             
            set.Add(str[i]);
        }
 
        // Stores the required answer
        String res = "";
 
        // Loop to iterate over the set
        foreach(char i in set) {
            res += i;
        }
 
        // Return Answer
        return res;
    }
 
    // Driver Code
    public static void Main()
    {
        string []arr
            = { "your", "you", "or", "yo" };
 
        Console.WriteLine(minSubstr(arr));
    }
}
// This code is contributed by Samim Hossain Mondal.

Javascript




  <script>
      // JavaScript code for the above approach
      function minSubstr(s)
      {
       
          // Stores the concatenated string
          // of all the given strings
          let str = "";
 
          // Loop to iterate through all
          // the given strings
          for (let i = 0; i < s.length; i++) {
              str += s[i];
          }
 
          // Set to store the characters
          let set = new Set();
 
          // Loop to iterate over all
          // the characters in str
          for (let i = 0; i < str.length; i++) {
              set.add(str[i]);
          }
 
          // Stores the required answer
          let res = "";
 
 
          // Loop to iterate over the set
          for (let itr of set) {
              res += itr;
          }
 
          // Return Answer
          return res;
      }
 
      // Driver Code
 
      let arr
          = ["your", "you",
              "or", "yo"];
 
      document.write(minSubstr(arr));
 
 
// This code is contributed by Potta Lokesh
  </script>

 
 

Output
ruyo

 

Time Complexity: O(N*M), where M is the average length of strings in the given array
Auxiliary Space: O(1)

 


My Personal Notes arrow_drop_up
Recommended Articles
Page :

Start Your Coding Journey Now!