2000. Reverse Prefix of Word(Solution || Leetcode easy || Java)

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".

Example 2:

Input: word = "xyxzxe", ch = "z"
Output: "zxyxxe"
Explanation: The first and only occurrence of "z" is at index 3.
Reverse the part of word from 0 to 3 (inclusive), the resulting string is "zxyxxe".

Example 3:

Input: word = "abcd", ch = "z"
Output: "abcd"
Explanation: "z" does not exist in word.
You should not do any reverse operation, the resulting string is "abcd".

Constraints:

• 1 <= word.length <= 250
• word consists of lowercase English letters.
• ch is a lowercase English letter.

SOLUTION:

      class Solution {
    public String reversePrefix(String word, char ch) {
//if the given string do not contain the character return the same
//string unchanged
        if(word.indexOf(ch) == -1){
            return word;
        }

//Get the first occurence of ch and from that index reverse
// the string       
        int i = word.indexOf(ch);
        
        StringBuilder temp = new StringBuilder(word.substring(0,i+1));
        
        temp = temp.reverse();
        
        temp = temp.append(word.substring(i+1));
        
        return temp.toString();
    }
}

Runtime: 1 ms, faster than 88.68% of Java online submissions for Reverse Prefix of Word.

Memory Usage: 42.4 MB, less than 43.26% of Java online submissions for Reverse Prefix of Word.

Thank you for reading. If you have any queries then, please let me know in the comment section. I will surely be responsive toward it.