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Java-based LeetCode algorithm problem solutions, regularly updated

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package g1801_1900.s1816_truncate_sentence;

// #Easy #Array #String #2022_05_03_Time_2_ms_(65.71%)_Space_42.9_MB_(30.34%)

/**
 * 1816 - Truncate Sentence\.
 *
 * Easy
 *
 * A **sentence** is a list of words that are separated by a single space with no leading or trailing spaces. Each of the words consists of **only** uppercase and lowercase English letters (no punctuation).
 *
 * *   For example, `"Hello World"`, `"HELLO"`, and `"hello world hello world"` are all sentences.
 *
 * You are given a sentence `s` and an integer `k`. You want to **truncate** `s` such that it contains only the **first** `k` words. Return `s`_ after **truncating** it._
 *
 * **Example 1:**
 *
 * **Input:** s = "Hello how are you Contestant", k = 4
 *
 * **Output:** "Hello how are you"
 *
 * **Explanation:** 
 *
 * The words in s are ["Hello", "how" "are", "you", "Contestant"]. 
 *
 * The first 4 words are ["Hello", "how", "are", "you"]. 
 *
 * Hence, you should return "Hello how are you".
 *
 * **Example 2:**
 *
 * **Input:** s = "What is the solution to this problem", k = 4
 *
 * **Output:** "What is the solution"
 *
 * **Explanation:** 
 *
 * The words in s are ["What", "is" "the", "solution", "to", "this", "problem"]. 
 *
 * The first 4 words are ["What", "is", "the", "solution"].
 *
 * Hence, you should return "What is the solution".
 *
 * **Example 3:**
 *
 * **Input:** s = "chopper is not a tanuki", k = 5
 *
 * **Output:** "chopper is not a tanuki"
 *
 * **Constraints:**
 *
 * *   `1 <= s.length <= 500`
 * *   `k` is in the range `[1, the number of words in s]`.
 * *   `s` consist of only lowercase and uppercase English letters and spaces.
 * *   The words in `s` are separated by a single space.
 * *   There are no leading or trailing spaces.
**/
public class Solution {
    public String truncateSentence(String s, int k) {
        String[] words = s.split(" ");
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < k; i++) {
            sb.append(words[i]);
            sb.append(" ");
        }
        return sb.substring(0, sb.toString().length() - 1);
    }
}