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Find the most valued alphabet in the String
• Last Updated : 18 May, 2021

Given a string str, the task is to find the maximum valued alphabet in str. The value of a particular alphabet is defined as the difference in the indices of its last and the first occurrence. If there are multiple such alphabets then find the lexicographically smallest alphabet.
Examples:

Input: str = “abbba”
Output:
value(‘a’) = 4 – 0 = 4
value(‘b’) = 3 – 1 = 2
Input: str = “bbb”
Output:

Approach: The idea is to store the first and the last occurrences of each of the alphabets in two auxiliary arrays say first[] and last[]. Now, these two arrays can be used to find the maximum valued alphabet in the given string.
Below is the implementation of the above approach:

## C++

 `// C++ implementation of the approach``#include ``using` `namespace` `std;` `const` `int` `MAX = 26;` `// Function to return the maximum``// valued alphabet``char` `maxAlpha(string str, ``int` `len)``{` `    ``// To store the first and the last``    ``// occurrence of all the characters``    ``int` `first[MAX], last[MAX];` `    ``// Set the first and the last occurrence``    ``// of all the characters to -1``    ``for` `(``int` `i = 0; i < MAX; i++) {``        ``first[i] = -1;``        ``last[i] = -1;``    ``}` `    ``// Update the occurrences of the characters``    ``for` `(``int` `i = 0; i < len; i++) {` `        ``int` `index = (str[i] - ``'a'``);` `        ``// Only set the first occurrence if``        ``// it hasn't already been set``        ``if` `(first[index] == -1)``            ``first[index] = i;` `        ``last[index] = i;``    ``}` `    ``// To store the result``    ``int` `ans = -1, maxVal = -1;` `    ``// For every alphabet``    ``for` `(``int` `i = 0; i < MAX; i++) {` `        ``// If current alphabet doesn't appear``        ``// in the given string``        ``if` `(first[i] == -1)``            ``continue``;` `        ``// If the current character has``        ``// the highest value so far``        ``if` `((last[i] - first[i]) > maxVal) {``            ``maxVal = last[i] - first[i];``            ``ans = i;``        ``}``    ``}` `    ``return` `(``char``)(ans + ``'a'``);``}` `// Driver code``int` `main()``{``    ``string str = ``"abbba"``;``    ``int` `len = str.length();` `    ``cout << maxAlpha(str, len);` `    ``return` `0;``}`

## Java

 `// Java implementation of the approach``class` `GFG``{` `static` `int` `MAX = ``26``;` `// Function to return the maximum``// valued alphabet``static` `char` `maxAlpha(String str, ``int` `len)``{` `    ``// To store the first and the last``    ``// occurrence of all the characters``    ``int` `[]first = ``new` `int``[MAX];``    ``int` `[]last = ``new` `int``[MAX];` `    ``// Set the first and the last occurrence``    ``// of all the characters to -1``    ``for` `(``int` `i = ``0``; i < MAX; i++)``    ``{``        ``first[i] = -``1``;``        ``last[i] = -``1``;``    ``}` `    ``// Update the occurrences of the characters``    ``for` `(``int` `i = ``0``; i < len; i++)``    ``{` `        ``int` `index = (str.charAt(i) - ``'a'``);` `        ``// Only set the first occurrence if``        ``// it hasn't already been set``        ``if` `(first[index] == -``1``)``            ``first[index] = i;` `        ``last[index] = i;``    ``}` `    ``// To store the result``    ``int` `ans = -``1``, maxVal = -``1``;` `    ``// For every alphabet``    ``for` `(``int` `i = ``0``; i < MAX; i++)``    ``{` `        ``// If current alphabet doesn't appear``        ``// in the given String``        ``if` `(first[i] == -``1``)``            ``continue``;` `        ``// If the current character has``        ``// the highest value so far``        ``if` `((last[i] - first[i]) > maxVal)``        ``{``            ``maxVal = last[i] - first[i];``            ``ans = i;``        ``}``    ``}``    ``return` `(``char``)(ans + ``'a'``);``}` `// Driver code``public` `static` `void` `main(String[] args)``{``    ``String str = ``"abbba"``;``    ``int` `len = str.length();` `    ``System.out.print(maxAlpha(str, len));``}``}` `// This code is contributed by 29AjayKumar`

## Python

 `# Python implementation of the approach``MAX` `=` `26` `# Function to return the maximum``# valued alphabet``def` `maxAlpha(``str``, ``len``):` `    ``# To store the first and the last``    ``# occurrence of all the characters` `    ``# Set the first and the last occurrence``    ``# of all the characters to -1``    ` `    ``first ``=` `[``-``1` `for` `x ``in` `range``(``MAX``)]``    ``last ``=` `[``-``1` `for` `x ``in` `range``(``MAX``)]``    ` `    ``# Update the occurrences of the characters``    ``for` `i ``in` `range``(``0``,``len``):` `        ``index ``=` `ord``(``str``[i])``-``97` `        ``# Only set the first occurrence if``        ``# it hasn't already been set``        ``if` `(first[index] ``=``=` `-``1``):``            ``first[index] ``=` `i` `        ``last[index] ``=` `i``    ` `    ``# To store the result``    ``ans ``=` `-``1``    ``maxVal ``=` `-``1` `    ``# For every alphabet``    ``for` `i ``in` `range``(``0``,``MAX``):` `        ``# If current alphabet doesn't appear``        ``# in the given string``        ``if` `(first[i] ``=``=` `-``1``):``            ``continue` `        ``# If the current character has``        ``# the highest value so far``        ``if` `((last[i] ``-` `first[i]) > maxVal):``            ``maxVal ``=` `last[i] ``-` `first[i];``            ``ans ``=` `i` `    ``return` `chr``(ans ``+` `97``)` `# Driver code``str` `=` `"abbba"``len` `=` `len``(``str``)` `print``(maxAlpha(``str``, ``len``))` `# This code is contributed by Sanjit_Prasad`

## C#

 `// C# implementation of the approach``using` `System;` `class` `GFG``{``static` `int` `MAX = 26;` `// Function to return the maximum``// valued alphabet``static` `char` `maxAlpha(String str, ``int` `len)``{` `    ``// To store the first and the last``    ``// occurrence of all the characters``    ``int` `[]first = ``new` `int``[MAX];``    ``int` `[]last = ``new` `int``[MAX];` `    ``// Set the first and the last occurrence``    ``// of all the characters to -1``    ``for` `(``int` `i = 0; i < MAX; i++)``    ``{``        ``first[i] = -1;``        ``last[i] = -1;``    ``}` `    ``// Update the occurrences of the characters``    ``for` `(``int` `i = 0; i < len; i++)``    ``{` `        ``int` `index = (str[i] - ``'a'``);` `        ``// Only set the first occurrence if``        ``// it hasn't already been set``        ``if` `(first[index] == -1)``            ``first[index] = i;` `        ``last[index] = i;``    ``}` `    ``// To store the result``    ``int` `ans = -1, maxVal = -1;` `    ``// For every alphabet``    ``for` `(``int` `i = 0; i < MAX; i++)``    ``{` `        ``// If current alphabet doesn't appear``        ``// in the given String``        ``if` `(first[i] == -1)``            ``continue``;` `        ``// If the current character has``        ``// the highest value so far``        ``if` `((last[i] - first[i]) > maxVal)``        ``{``            ``maxVal = last[i] - first[i];``            ``ans = i;``        ``}``    ``}``    ``return` `(``char``)(ans + ``'a'``);``}` `// Driver code``public` `static` `void` `Main(String[] args)``{``    ``String str = ``"abbba"``;``    ``int` `len = str.Length;` `    ``Console.Write(maxAlpha(str, len));``}``}` `// This code is contributed by Rajput-Ji`

## Javascript

 ``
Output:

`a`

Time Complexity: O(N)

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