每日一題 8/24(找出清單中大於目標的最小順序,如果沒有則返回清單中的第一個字母)

 You are given an array of characters letters that is sorted in non-decreasing order, and a character target. There are at least two different characters in letters.

Return the smallest character in letters that is lexicographically greater than target. If such a character does not exist, return the first character in letters.

 

Example 1:

Input: letters = ["c","f","j"], target = "a"
Output: "c"
Explanation: The smallest character that is lexicographically greater than 'a' in letters is 'c'.

Example 2:

Input: letters = ["c","f","j"], target = "c"
Output: "f"
Explanation: The smallest character that is lexicographically greater than 'c' in letters is 'f'.

Example 3:

Input: letters = ["x","x","y","y"], target = "z"
Output: "x"
Explanation: There are no characters in letters that is lexicographically greater than 'z' so we return letters[0].

 

Constraints:

• 2 <= letters.length <= 104
• letters[i] is a lowercase English letter.
• letters is sorted in non-decreasing order.
• letters contains at least two different characters.
• target is a lowercase English letter.

class Solution:

    def nextGreatestLetter(self, letters: List[str], target: str) -> str:

        target_num=ord(target)

        letters_num=list(map(ord,letters))

        smllest=200

        for i in letters_num:

            if i > target_num:

                smllest=min(i,smllest)

        if smllest!=200:

            return chr(smllest)

        else:

            return letters[0]

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