2000. Reverse Prefix of Word (C++)

간단한 Two Pointer 문제!  틈나는대로 풀고있다 ㅋㅋㅋ 확실히 풀리니까 재밌구만. 

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 : 

char * reversePrefix(char * word, char ch){
    int len = strlen(word);
    int position = 0;
    
    for(int i = 0; i < len; i++) {
        if(word[i] == ch) {
            position = i;
            break;
        }
    }
    int left = 0;
    int right = position;
    while( left < right ) {
        char tmp;
        tmp = word[left];
        word[left] = word[right];
        word[right] = tmp;
        left++;
        right--;
    }
    return word;
}

 

정답 ~