{ "data": { "question": { "questionId": "2708", "questionFrontendId": "2573", "boundTopicId": null, "title": "Find the String with LCP", "titleSlug": "find-the-string-with-lcp", "content": "
We define the lcp
matrix of any 0-indexed string word
of n
lowercase English letters as an n x n
grid such that:
lcp[i][j]
is equal to the length of the longest common prefix between the substrings word[i,n-1]
and word[j,n-1]
.Given an n x n
matrix lcp
, return the alphabetically smallest string word
that corresponds to lcp
. If there is no such string, return an empty string.
A string a
is lexicographically smaller than a string b
(of the same length) if in the first position where a
and b
differ, string a
has a letter that appears earlier in the alphabet than the corresponding letter in b
. For example, "aabd"
is lexicographically smaller than "aaca"
because the first position they differ is at the third letter, and 'b'
comes before 'c'
.
\n
Example 1:
\n\n\nInput: lcp = [[4,0,2,0],[0,3,0,1],[2,0,2,0],[0,1,0,1]]\nOutput: "abab"\nExplanation: lcp corresponds to any 4 letter string with two alternating letters. The lexicographically smallest of them is "abab".\n\n\n
Example 2:
\n\n\nInput: lcp = [[4,3,2,1],[3,3,2,1],[2,2,2,1],[1,1,1,1]]\nOutput: "aaaa"\nExplanation: lcp corresponds to any 4 letter string with a single distinct letter. The lexicographically smallest of them is "aaaa". \n\n\n
Example 3:
\n\n\nInput: lcp = [[4,3,2,1],[3,3,2,1],[2,2,2,1],[1,1,1,3]]\nOutput: ""\nExplanation: lcp[3][3] cannot be equal to 3 since word[3,...,3] consists of only a single letter; Thus, no answer exists.\n\n\n
\n
Constraints:
\n\n1 <= n ==
lcp.length ==
lcp[i].length
<= 1000
0 <= lcp[i][j] <= n
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Most standard library headers are already included automatically for your convenience.
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