Package g1901_2000.s1923_longest_common_subpath

Class Solution

  • public class Solution
extends Object
    1923 - Longest Common Subpath.

    Hard

    There is a country of n cities numbered from 0 to n - 1. In this country, there is a road connecting every pair of cities.

    There are m friends numbered from 0 to m - 1 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 more than once , but the same city will not be listed consecutively.

    Given an integer n and a 2D integer array paths where paths[i] is an integer array representing the path of the ith friend, return the length of the longest common subpath that is shared by every friend’s path, or 0 if there is no common subpath at all.

    A subpath of a path is a contiguous sequence of cities within that path.

    Example 1:

    Input: n = 5, paths = [[0,1,2,3,4], [2,3,4], [4,0,1,2,3]]

    Output: 2

    Explanation: The longest common subpath is [2,3].

    Example 2:

    Input: n = 3, paths = [[0],[1],[2]]

    Output: 0

    Explanation: There is no common subpath shared by the three paths.

    Example 3:

    Input: n = 5, paths = [[0,1,2,3,4], [4,3,2,1,0]]

    Output: 1

    Explanation: The possible longest common subpaths are [0], [1], [2], [3], and [4]. All have a length of 1.

    Constraints:

    • 1 <= n <= 105
    • m == paths.length
    • 2 <= m <= 105
    • sum(paths[i].length) <= 105
    • 0 <= paths[i][j] < n
    • The same city is not listed multiple times consecutively in paths[i].

    • Constructor Detail

      • Solution

        public Solution()

    • Method Detail

      • longestCommonSubpath

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