Package g2001_2100.s2014_longest_subsequence_repeated_k_times

Class Solution

java.lang.Object

g2001_2100.s2014_longest_subsequence_repeated_k_times.Solution

public class Solution
extends Object

2014 - Longest Subsequence Repeated k Times.<p>Hard</p> <p>You are given a string <code>s</code> of length <code>n</code>, and an integer <code>k</code>. You are tasked to find the <strong>longest subsequence repeated</strong> <code>k</code> times in string <code>s</code>.</p> <p>A <strong>subsequence</strong> is a string that can be derived from another string by deleting some or no characters without changing the order of the remaining characters.</p> <p>A subsequence <code>seq</code> is <strong>repeated</strong> <code>k</code> times in the string <code>s</code> if <code>seq * k</code> is a subsequence of <code>s</code>, where <code>seq * k</code> represents a string constructed by concatenating <code>seq</code> <code>k</code> times.</p> <ul> <li>For example, <code>&quot;bba&quot;</code> is repeated <code>2</code> times in the string <code>&quot;bababcba&quot;</code>, because the string <code>&quot;bbabba&quot;</code>, constructed by concatenating <code>&quot;bba&quot;</code> <code>2</code> times, is a subsequence of the string <code>&quot;**b**a**bab**c**ba**&quot;</code>.</li> </ul> <p>Return <em>the <strong>longest subsequence repeated</strong></em> <code>k</code> <em>times in string</em> <code>s</code><em>. If multiple such subsequences are found, return the <strong>lexicographically largest</strong> one. If there is no such subsequence, return an <strong>empty</strong> string</em>.</p> <p><strong>Example 1:</strong></p> <p><img src="https://assets.leetcode.com/uploads/2021/08/30/longest-subsequence-repeat-k-times.png" alt="example 1" /></p> <p><strong>Input:</strong> s = &ldquo;letsleetcode&rdquo;, k = 2</p> <p><strong>Output:</strong> &ldquo;let&rdquo;</p> <p><strong>Explanation:</strong> There are two longest subsequences repeated 2 times: &ldquo;let&rdquo; and &ldquo;ete&rdquo;. &ldquo;let&rdquo; is the lexicographically largest one.</p> <p><strong>Example 2:</strong></p> <p><strong>Input:</strong> s = &ldquo;bb&rdquo;, k = 2</p> <p><strong>Output:</strong> &ldquo;b&rdquo;</p> <p><strong>Explanation:</strong> The longest subsequence repeated 2 times is &ldquo;b&rdquo;.</p> <p><strong>Example 3:</strong></p> <p><strong>Input:</strong> s = &ldquo;ab&rdquo;, k = 2</p> <p><strong>Output:</strong> &quot;&quot;</p> <p><strong>Explanation:</strong> There is no subsequence repeated 2 times. Empty string is returned.</p> <p><strong>Constraints:</strong></p> <ul> <li><code>n == s.length</code></li> <li><code>2 <= n, k <= 2000</code></li> <li><code>2 <= n < k * 8</code></li> <li><code>s</code> consists of lowercase English letters.</li> </ul>

Constructor Summary

Constructors

Constructor	Description
Solution()

Method Summary

Modifier and Type	Method	Description
String	longestSubsequenceRepeatedK(String s, int k)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Solution

public Solution()

Method Details

longestSubsequenceRepeatedK

public String longestSubsequenceRepeatedK(String s,
 int k)