# Lexicographically largest string formed from the characters in range L and R

Given a string S and a range L and R, the task is to print the lexicographically largest string that can be formed from the characters in range L and R.

Examples:

```Input: str = "thgyfh", L = 2, R = 6
Output: yhhgf

Input: str = "striver", L = 3, R = 5
Output: vri
```

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach:

• Iterate from min(L, R) to max(L, R) and increase the frequencies of characters in a freq[] array.
• Iterate from 25 to 0 and print the number of times every character occurs to get the lexicographically largest string.

The common point of mistake which everyone does is they iterate from L to R instead of min(L, R) to max(L, R).

Below is the implementation of the above approach:

## C++

 `// C++ program to print the ` `// lexicographically largest string that ` `// can be formed from the characters ` `// in range L and R ` ` `  `#include ` `using` `namespace` `std; ` ` `  `// Function to return the lexicographically largest string ` `string printLargestString(string s, ``int` `l, ``int` `r) ` `{ ` `    ``// hash array ` `    ``int` `freq = { 0 }; ` ` `  `    ``// make 0-based indexing ` `    ``l--; ` `    ``r--; ` ` `  `    ``// iterate and count frequencies of character ` `    ``for` `(``int` `i = min(l, r); i <= max(l, r); i++) { ` `        ``freq[s[i] - ``'a'``]++; ` `    ``} ` ` `  `    ``// ans string ` `    ``string ans = ``""``; ` ` `  `    ``// iterate in frequency array ` `    ``for` `(``int` `i = 25; i >= 0; i--) { ` ` `  `        ``// add til all characters ` `        ``// are added ` `        ``while` `(freq[i]) { ` `            ``ans += ``char``(``'a'` `+ i); ` `            ``freq[i]--; ` `        ``} ` `    ``} ` ` `  `    ``return` `ans; ` `} ` ` `  `// Driver Code ` `int` `main() ` `{ ` `    ``string s = ``"striver"``; ` `    ``int` `l = 3, r = 5; ` `    ``cout << printLargestString(s, l, r); ` `    ``return` `0; ` `} `

## Java

 `// Java program to print the  ` `// lexicographically largest String that  ` `// can be formed from the characters  ` `// in range L and R   ` ` `  `class` `GFG { ` ` `  `// Function to return the lexicographically largest String  ` `    ``static` `String printLargestString(String s, ``int` `l, ``int` `r) { ` `        ``// hash array  ` `        ``int` `freq[] = ``new` `int``[``26``]; ` ` `  `        ``// make 0-based indexing  ` `        ``l--; ` `        ``r--; ` ` `  `        ``// iterate and count frequencies of character  ` `        ``for` `(``int` `i = Math.min(l, r); i <= Math.max(l, r); i++) { ` `            ``freq[s.charAt(i) - ``'a'``]++; ` `        ``} ` ` `  `        ``// ans String  ` `        ``String ans = ``""``; ` ` `  `        ``// iterate in frequency array  ` `        ``for` `(``int` `i = ``25``; i >= ``0``; i--) { ` ` `  `            ``// add til all characters  ` `            ``// are added  ` `            ``while` `(freq[i] > ``0``) { ` `                ``ans += (``char``) (``'a'` `+ i); ` `                ``freq[i]--; ` `            ``} ` `        ``} ` ` `  `        ``return` `ans; ` `    ``} ` ` `  `// Driver Code  ` `    ``public` `static` `void` `main(String[] args) { ` ` `  `        ``String s = ``"striver"``; ` `        ``int` `l = ``3``, r = ``5``; ` `        ``System.out.println(printLargestString(s, l, r)); ` ` `  `    ``} ` `} ` `/* This JAVA code is contributed by 29AjayKumar*/`

## Python 3

 `# Python 3 program to print the ` `# lexicographically largest string that ` `# can be formed from the characters ` `# in range L and R ` ` `  `# Function to return the lexicographically  ` `# largest string ` `def` `printLargestString(s, l, r): ` ` `  `    ``# hash array ` `    ``freq ``=` `[``0``] ``*` `26` ` `  `    ``# make 0-based indexing ` `    ``l ``-``=` `1` `    ``r ``-``=` `1` ` `  `    ``# iterate and count frequencies of character ` `    ``for` `i ``in` `range``(``min``(l, r), ``max``(l, r) ``+` `1``) : ` `        ``freq[``ord``(s[i]) ``-` `ord``(``'a'``)] ``+``=` `1` ` `  `    ``# ans string ` `    ``ans ``=` `"" ` ` `  `    ``# iterate in frequency array ` `    ``for` `i ``in` `range``(``25``, ``-``1``, ``-``1``): ` ` `  `        ``# add til all characters are added ` `        ``while` `(freq[i]): ` `            ``ans ``+``=` `chr``(``ord``(``'a'``) ``+` `i) ` `            ``freq[i] ``-``=` `1` ` `  `    ``return` `ans ` ` `  `# Driver Code ` `if` `__name__ ``=``=` `"__main__"``: ` `     `  `    ``s ``=` `"striver"` `    ``l ``=` `3` `    ``r ``=` `5` `    ``print``(printLargestString(s, l, r)) ` ` `  `# This code is contributed by ita_c `

## C#

 `// C# program to print the lexicographically ` `// largest String that can be formed from the  ` `// characters in range L and R ` `using` `System; ` ` `  `class` `GFG ` `{ ` ` `  `// Function to return the lexicographically  ` `// largest String  ` `static` `String printLargestString(String s,  ` `                                 ``int` `l, ``int` `r)  ` `{ ` `    ``// hash array  ` `    ``int` `[]freq = ``new` `int``; ` ` `  `    ``// make 0-based indexing  ` `    ``l--; ` `    ``r--; ` ` `  `    ``// iterate and count frequencies ` `    ``// of character  ` `    ``for` `(``int` `i = Math.Min(l, r);  ` `             ``i <= Math.Max(l, r); i++) ` `    ``{ ` `        ``freq[s[i] - ``'a'``]++; ` `    ``} ` ` `  `    ``// ans String  ` `    ``String ans = ``""``; ` ` `  `    ``// iterate in frequency array  ` `    ``for` `(``int` `i = 25; i >= 0; i--) ` `    ``{ ` ` `  `        ``// add til all characters  ` `        ``// are added  ` `        ``while` `(freq[i] > 0)  ` `        ``{ ` `            ``ans += (``char``) (``'a'` `+ i); ` `            ``freq[i]--; ` `        ``} ` `    ``} ` ` `  `    ``return` `ans; ` `} ` ` `  `// Driver Code  ` `public` `static` `void` `Main()  ` `{ ` `    ``String s = ``"striver"``; ` `    ``int` `l = 3, r = 5; ` `    ``Console.Write(printLargestString(s, l, r)); ` `} ` `} ` ` `  `// This code is contributed by 29AjayKumar `

Output:

```vri
```

Time Complexity – O(N)
Each element gets added to the frequency table only once which takes O(1) and is appended to string which also takes O(1).

My Personal Notes arrow_drop_up Striver(underscore)79 at Codechef and codeforces D

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.

Article Tags :
Practice Tags :

Be the First to upvote.

Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.