1165

1165. Single-Row Keyboard (Easy)

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 <= 104
• word[i] is an English lowercase letter.

Companies:
Google

Related Topics:
Hash Table, String

Solution 1.

// OJ: https://leetcode.com/problems/single-row-keyboard/
// Author: github.com/lzl124631x
// Time: O(N)
// Space: O(1)
class Solution {
public:
    int calculateTime(string keyboard, string word) {
        unordered_map<char, int> m;
        for (int i = 0; i < 26; ++i) m[keyboard[i]] = i;
        int prev = 0, ans = 0;
        for (char c : word) {
            int i = m[c];
            ans += abs(prev - i);
            prev = i;
        }
        return ans;
    }
};