LeetCode解题报告（504）-- 1974. Minimum Time to Type Word Using Special Typewriter

Problem

There is a special typewriter with lowercase English letters 'a' to 'z' arranged in a circle with a pointer. A character can only be typed if the pointer is pointing to that character. The pointer is initially pointing to the character 'a'.

Each second, you may perform one of the following operations:

• Move the pointer one character counterclockwise or clockwise.
• Type the character the pointer is currently on.

Given a string word, return the minimum number of seconds to type out the characters in word.

Example 1:

Input: word = "abc"
Output: 5
Explanation: 
The characters are printed as follows:
- Type the character 'a' in 1 second since the pointer is initially on 'a'.
- Move the pointer clockwise to 'b' in 1 second.
- Type the character 'b' in 1 second.
- Move the pointer clockwise to 'c' in 1 second.
- Type the character 'c' in 1 second.

Example 2:

Input: word = "bza"
Output: 7
Explanation:
The characters are printed as follows:
- Move the pointer clockwise to 'b' in 1 second.
- Type the character 'b' in 1 second.
- Move the pointer counterclockwise to 'z' in 2 seconds.
- Type the character 'z' in 1 second.
- Move the pointer clockwise to 'a' in 1 second.
- Type the character 'a' in 1 second.

Example 3:

Input: word = "zjpc"
Output: 34
Explanation:
The characters are printed as follows:
- Move the pointer counterclockwise to 'z' in 1 second.
- Type the character 'z' in 1 second.
- Move the pointer clockwise to 'j' in 10 seconds.
- Type the character 'j' in 1 second.
- Move the pointer clockwise to 'p' in 6 seconds.
- Type the character 'p' in 1 second.
- Move the pointer counterclockwise to 'c' in 13 seconds.
- Type the character 'c' in 1 second.

Constraints:

• 1 <= word.length <= 100
• word consists of lowercase English letters.

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Analysis

  这道题目给出了一个圆盘的打字机，给了一个字符串word，起始指针指向a，每打一个字符的cost是移动的距离，问打完这个字符串最小的cost是多少。这道题目实际上就是问从某个字符到另一个字符，最短的路径是什么。无非就两种选择，顺时针和逆时针。顺时针就是end - start，逆时针就是start - end，为了统一处理都加上26变成正数，然后对26取余即可。

Solution

  无。

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Code

class Solution {
public:
    int minTimeToType(string word) {
        int result = 0;
        char pre = 'a';
        for (char ch: word) {
            result += min((ch - pre + 26) % 26, (pre - ch + 26) % 26);
            pre = ch;
        }
        return result + word.size();
    }
};

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Summary

  这道题目本质就是考察在循环数组中如何处理下标问题。这道题目的分享到这里，感谢你的支持！