1165. 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.

class Solution {
public:
    int calculateTime(string keyboard, string word) {
        map<char, int> keyIndex;
        for(int i = 0; i < keyboard.length(); ++i) {
            keyIndex[keyboard[i]] = i;
        }

        int finger = 0;
        int res = 0;
        for(int i = 0; i < word.length(); ++i) {
            res += abs(keyIndex[word[i]] - finger);
            finger = keyIndex[word[i]];
        }

        return res;
    }
};