2000. Reverse Prefix of Word

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.

class Solution {
public:
    string reversePrefix(string word, char ch) {
        int idx = -1;
        for(int i = 0; i < word.size(); i++) {
            if(word[i] == ch) {
                idx = i;
                break;
            }
        }
        if(idx != -1) {
            reverse(begin(word), begin(word) + idx + 1);
        }
        return word;
    }
};