{ "data": { "question": { "questionId": "2051", "questionFrontendId": "1923", "boundTopicId": null, "title": "Longest Common Subpath", "titleSlug": "longest-common-subpath", "content": "

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.

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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.

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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.

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

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Example 1:

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\nInput: n = 5, paths = [[0,1,2,3,4],\n                       [2,3,4],\n                       [4,0,1,2,3]]\nOutput: 2\nExplanation: The longest common subpath is [2,3].\n
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Example 2:

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\nInput: n = 3, paths = [[0],[1],[2]]\nOutput: 0\nExplanation: There is no common subpath shared by the three paths.\n
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Example 3:

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\nInput: n = 5, paths = [[0,1,2,3,4],\n                       [4,3,2,1,0]]\nOutput: 1\nExplanation: The possible longest common subpaths are [0], [1], [2], [3], and [4]. All have a length of 1.
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Constraints:

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