# LeetCode 1165. Single-Row Keyboard

## Description

https://leetcode.com/problems/single-row-keyboard/

There is a special keyboard with all keys in a single row.

Given a string `keyboard` of length 26 indicating the layout of the keyboard (indexed from 0 to 25), initially your finger is at index 0. To type a character, you have to move your finger to the index of the desired character. The time taken to move your finger from index `i` to index `j` is `|i - j|`.

You want to type a string `word`. Write a function to calculate how much time it takes to type it with one finger.

Example 1:

```Input: keyboard = "abcdefghijklmnopqrstuvwxyz", word = "cba"
Output: 4
Explanation: The index moves from 0 to 2 to write 'c' then to 1 to write 'b' then to 0 again to write 'a'.
Total time = 2 + 1 + 1 = 4.
```

Example 2:

```Input: keyboard = "pqrstuvwxyzabcdefghijklmno", word = "leetcode"
Output: 73
```

Constraints:

• `keyboard.length == 26`
• `keyboard` contains each English lowercase letter exactly once in some order.
• `1 <= word.length <= 10^4`
• `word[i]` is an English lowercase letter.

## Explanation

Subtract previous index and add time.

## Python Solution

``````class Solution:
def calculateTime(self, keyboard: str, word: str) -> int:

mapping = {}

for i, c in enumerate(keyboard):
mapping[c] = i

total_time = 0
prev = 0

for c in word:
index = mapping[c]
total_time += abs(index - prev)
prev = index