# Count of buttons pressed in a keypad mobile

• Difficulty Level : Medium
• Last Updated : 26 Mar, 2021

Given a string str, the task is to count how many times the keys will be pressed in total if there is a mobile like below image to form the given string.

Examples:

Input: str = “abcdef”
Output: 12
1 for a, 2 for b, 3 for c, 1 for d, 2 for e and 3 for f
Total = 1 + 2 + 3 + 1 + 2 + 3 = 12
Input: str = “ssss”
Output: 16

Approach: Use an array to store how many times a button has to be pressed for typing a particular character and then traverse the given string character by character and add all the corresponding count of key presses to the sum variable.
Below is the implementation of the above approach:

## C++

 `// C++ implementation of the approach``#include ``using` `namespace` `std;` `// Array to store how many times a button``// has to be pressed for typing``// a particular character``const` `int` `arr[] = { 1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3, 1,``                    ``2, 3, 1, 2, 3, 4, 1, 2, 3, 1, 2, 3, 4 };` `// Function to return the count of``// buttons pressed to type the given string``int` `countKeyPressed(string str, ``int` `len)``{``    ``int` `count = 0;` `    ``// Count the key presses``    ``for` `(``int` `i = 0; i < len; i++)``        ``count = count + arr[str[i] - ``'a'``];` `    ``// Return the required count``    ``return` `count;``}` `// Driver code``int` `main()``{``    ``string str = ``"abcdef"``;``    ``int` `len = str.length();``    ``cout << countKeyPressed(str, len);` `    ``return` `0;``}`

## Java

 `// Java implementation of the approach``class` `GFG {` `    ``// Array to store how many times a button``    ``// has to be pressed for typing``    ``// a particular character``    ``static` `final` `int` `arr[] = { ``1``, ``2``, ``3``, ``1``, ``2``, ``3``, ``1``, ``2``, ``3``, ``1``, ``2``, ``3``, ``1``,``                               ``2``, ``3``, ``1``, ``2``, ``3``, ``4``, ``1``, ``2``, ``3``, ``1``, ``2``, ``3``, ``4` `};` `    ``// Function to return the count of``    ``// buttons pressed to type the given string``    ``public` `static` `int` `countKeyPressed(String str, ``int` `len)``    ``{``        ``int` `count = ``0``;` `        ``// Count the key presses``        ``for` `(``int` `i = ``0``; i < len; i++)``            ``count = count + arr[str.charAt(i) - ``'a'``];` `        ``// Return the required count``        ``return` `count;``    ``}` `    ``// Driver code``    ``public` `static` `void` `main(String[] args)``    ``{``        ``String str = ``"abcdef"``;``        ``int` `len = str.length();``        ``System.out.print(countKeyPressed(str, len));``    ``}``}`

## Python3

 `# Python3 implementation of the approach` `# Array to store how many times a button``# has to be pressed for typing``# a particular character``arr ``=` `[ ``1``, ``2``, ``3``, ``1``, ``2``, ``3``, ``1``, ``2``, ``3``, ``1``, ``2``, ``3``, ``1``,``        ``2``, ``3``, ``1``, ``2``, ``3``, ``4``, ``1``, ``2``, ``3``, ``1``, ``2``, ``3``, ``4` `];` `# Function to return the count of``# buttons pressed to type the given string``def` `countKeyPressed(string, length) :``    ``count ``=` `0``;` `    ``# Count the key presses``    ``for` `i ``in` `range``(length) :``        ``count ``+``=` `arr[``ord``(string[i]) ``-` `ord``(``'a'``)];` `    ``# Return the required count``    ``return` `count;` `# Driver code``if` `__name__ ``=``=` `"__main__"` `:``    ``string ``=` `"abcdef"``;``    ``length ``=` `len``(string);``    ` `    ``print``(countKeyPressed(string, length));` `# This code is contributed by Ryuga`

## C#

 `// C# implementation of the approach``using` `System;``class` `GFG {` `    ``// Array to store how many times a button``    ``// has to be pressed for typing``    ``// a particular character``    ``static` `readonly` `int``[] arr = { 1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3, 1,``                                  ``2, 3, 1, 2, 3, 4, 1, 2, 3, 1, 2, 3, 4 };` `    ``// Function to return the count of``    ``// buttons pressed to type the given string``    ``public` `static` `int` `countKeyPressed(String str, ``int` `len)``    ``{``        ``int` `count = 0;` `        ``// Count the key presses``        ``for` `(``int` `i = 0; i < len; i++)``            ``count = count + arr[str[i] - ``'a'``];` `        ``// Return the required count``        ``return` `count;``    ``}` `    ``// Driver code``    ``public` `static` `void` `Main()``    ``{``        ``String str = ``"abcdef"``;``        ``int` `len = str.Length;``        ``Console.Write(countKeyPressed(str, len));``    ``}``}`

## PHP

 ``

## Javascript

 ``
Output:
`12`

Time Complexity: O(n)

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