Package g1901_2000.s1923_longest_common_subpath

Class Solution

java.lang.Object
g1901_2000.s1923_longest_common_subpath.Solution
public class Solution extends Object
1923 - Longest Common Subpath.<p>Hard</p> <p>There is a country of <code>n</code> cities numbered from <code>0</code> to <code>n - 1</code>. In this country, there is a road connecting <strong>every pair</strong> of cities.</p> <p>There are <code>m</code> friends numbered from <code>0</code> to <code>m - 1</code> who are traveling through the country. Each one of them will take a path consisting of some cities. Each path is represented by an integer array that contains the visited cities in order. The path may contain a city <strong>more than once</strong> , but the same city will not be listed consecutively.</p> <p>Given an integer <code>n</code> and a 2D integer array <code>paths</code> where <code>paths[i]</code> is an integer array representing the path of the <code>i<sup>th</sup></code> friend, return <em>the length of the <strong>longest common subpath</strong> that is shared by <strong>every</strong> friend&rsquo;s path, or</em> <code>0</code> <em>if there is no common subpath at all</em>.</p> <p>A <strong>subpath</strong> of a path is a contiguous sequence of cities within that path.</p> <p><strong>Example 1:</strong></p> <p><strong>Input:</strong> n = 5, paths = [[0,1,2,3,4], [2,3,4], [4,0,1,2,3]]</p> <p><strong>Output:</strong> 2</p> <p><strong>Explanation:</strong> The longest common subpath is [2,3].</p> <p><strong>Example 2:</strong></p> <p><strong>Input:</strong> n = 3, paths = [[0],[1],[2]]</p> <p><strong>Output:</strong> 0</p> <p><strong>Explanation:</strong> There is no common subpath shared by the three paths.</p> <p><strong>Example 3:</strong></p> <p><strong>Input:</strong> n = 5, paths = [[0,1,2,3,4], [4,3,2,1,0]]</p> <p><strong>Output:</strong> 1</p> <p><strong>Explanation:</strong> The possible longest common subpaths are [0], [1], [2], [3], and [4]. All have a length of 1.</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= n <= 10<sup>5</sup></code></li> <li><code>m == paths.length</code></li> <li><code>2 <= m <= 10<sup>5</sup></code></li> <li><code>sum(paths[i].length) <= 10<sup>5</sup></code></li> <li><code>0 <= paths[i][j] < n</code></li> <li>The same city is not listed multiple times consecutively in <code>paths[i]</code>.</li> </ul>

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • longestCommonSubpath

      public int longestCommonSubpath(int n, int[][] paths)