Single-Row Keyboard

给一个字符串作为keyboard, 问另一个字符串中每个字符在这个keyboard上的距离差的和是多少.

class Solution {
    public int calculateTime(String keyboard, String word) {
        Map<Character, Integer> map = new HashMap<>();
        for(int i = 0; i < keyboard.length(); i++) {
            map.put(keyboard.charAt(i), i);
        }
        int sum = 0;
        int prev = 0;
        for(char c : word.toCharArray()){
            if(prev != '1') {
                sum += Math.abs(map.get(c) - prev);
            }
            prev = map.get(c);
        }
        return sum;
    }
}