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.

Example 

class Solution {
    public int calculateTime(String keyboard, String word) {

        Map<Character,Integer> keyMap = new HashMap<>();
        for (int i = 0; i < keyboard.length(); i++) {
            keyMap.put(keyboard.charAt(i), i);
        }
        int total_moves = 0;
        int curPosition = 0;
        for (int i = 0; i < word.length(); i++) {
            char cur = word.charAt(i);
            int target = keyMap.get(cur);
            total_moves += Math.abs(curPosition - target);
            curPosition = target;
        }
        return total_moves;
    }
}

Categories: Map

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s