g0901_1000.s0917_reverse_only_letters.Solution Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of leetcode-in-java21 Show documentation

Java-based LeetCode algorithm problem solutions, regularly updated

There is a newer version: 1.38

package g0901_1000.s0917_reverse_only_letters;

// #Easy #String #Two_Pointers #2022_03_29_Time_0_ms_(100.00%)_Space_39.9_MB_(99.08%)

/**
 * 917 - Reverse Only Letters\.
 *
 * Easy
 *
 * Given a string `s`, reverse the string according to the following rules:
 *
 * *   All the characters that are not English letters remain in the same position.
 * *   All the English letters (lowercase or uppercase) should be reversed.
 *
 * Return `s` _after reversing it_.
 *
 * **Example 1:**
 *
 * **Input:** s = "ab-cd"
 *
 * **Output:** "dc-ba"
 *
 * **Example 2:**
 *
 * **Input:** s = "a-bC-dEf-ghIj"
 *
 * **Output:** "j-Ih-gfE-dCba"
 *
 * **Example 3:**
 *
 * **Input:** s = "Test1ng-Leet=code-Q!"
 *
 * **Output:** "Qedo1ct-eeLg=ntse-T!"
 *
 * **Constraints:**
 *
 * *   `1 <= s.length <= 100`
 * *   `s` consists of characters with ASCII values in the range `[33, 122]`.
 * *   `s` does not contain `'\"'` or `'\\'`.
**/
public class Solution {
    public String reverseOnlyLetters(String s) {
        char[] array = s.toCharArray();
        int i = 0;
        int j = array.length - 1;
        while (i < j) {
            if (Character.isLetter(array[i]) && Character.isLetter(array[j])) {
                char temp = array[i];
                array[i++] = array[j];
                array[j--] = temp;
            } else if (Character.isLetter(array[i])) {
                j--;
            } else if (Character.isLetter(array[j])) {
                i++;
            } else {
                i++;
                j--;
            }
        }
        return new String(array);
    }
}