g2101_2200.s2129_capitalize_the_title.Solution Maven / Gradle / Ivy

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Java-based LeetCode algorithm problem solutions, regularly updated

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package g2101_2200.s2129_capitalize_the_title;

// #Easy #String #2022_06_03_Time_2_ms_(94.22%)_Space_42.5_MB_(71.58%)

/**
 * 2129 - Capitalize the Title\.
 *
 * Easy
 *
 * You are given a string `title` consisting of one or more words separated by a single space, where each word consists of English letters. **Capitalize** the string by changing the capitalization of each word such that:
 *
 * *   If the length of the word is `1` or `2` letters, change all letters to lowercase.
 * *   Otherwise, change the first letter to uppercase and the remaining letters to lowercase.
 *
 * Return _the **capitalized**_ `title`.
 *
 * **Example 1:**
 *
 * **Input:** title = "capiTalIze tHe titLe"
 *
 * **Output:** "Capitalize The Title"
 *
 * **Explanation:** Since all the words have a length of at least 3, the first letter of each word is uppercase, and the remaining letters are lowercase.
 *
 * **Example 2:**
 *
 * **Input:** title = "First leTTeR of EACH Word"
 *
 * **Output:** "First Letter of Each Word"
 *
 * **Explanation:** 
 *
 * The word "of" has length 2, so it is all lowercase. 
 *
 * The remaining words have a length of at least 3, so the first letter of each remaining word is uppercase, and the remaining letters are lowercase.
 *
 * **Example 3:**
 *
 * **Input:** title = "i lOve leetcode"
 *
 * **Output:** "i Love Leetcode"
 *
 * **Explanation:** 
 *
 * The word "i" has length 1, so it is lowercase. 
 *
 * The remaining words have a length of at least 3, so the first letter of each remaining word is uppercase, and the remaining letters are lowercase.
 *
 * **Constraints:**
 *
 * *   `1 <= title.length <= 100`
 * *   `title` consists of words separated by a single space without any leading or trailing spaces.
 * *   Each word consists of uppercase and lowercase English letters and is **non-empty**.
**/
public class Solution {
    public String capitalizeTitle(String title) {
        StringBuilder sb = new StringBuilder();
        int i = 0;
        int j = 0;
        while (i < title.length()) {
            while (j < title.length() && title.charAt(j) != ' ') {
                sb.append(Character.toLowerCase(title.charAt(j)));
                j++;
            }
            int len = j - i;
            if (len > 2) {
                sb.setCharAt(i, Character.toUpperCase(title.charAt(i)));
            }
            if (j == title.length()) {
                break;
            }
            sb.append(title.charAt(j));
            i = ++j;
        }
        return sb.toString();
    }
}