[LeetCode]#2000. Reverse Prefix of Word

Environment: Python 3.8

Key technique: find, string

Given a 0-indexed string word and a character ch, reverse the segment of word that starts at index 0 and ends at the index of the first occurrence of ch (inclusive). If the character ch does not exist in word, do nothing.

• For example, if word = "abcdefd" and ch = "d", then you should reverse the segment that starts at 0 and ends at 3 (inclusive). The resulting string will be "dcbaefd".

Return the resulting string.

Example 1:

Input: word = "abcdefd", ch = "d"
Output: "dcbaefd"
Explanation: The first occurrence of "d" is at index 3. 
Reverse the part of word from 0 to 3 (inclusive), the resulting string is "dcbaefd".

Analysis:

1. find ch location in word.
2. Reverse green string
3. add remaining string

Solution:

class Solution:
    def reversePrefix(self, word, ch):
        i=word.find(ch)
        return word[:i+1][::-1] + word[i+1::]

Submissions:

Reference:

https://leetcode.com/problems/reverse-prefix-of-word/discuss/1574118/Python-solution