LCS - Longest Common Substring

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A string is finite sequence of characters over a non-empty finite set Σ.

In this problem, Σ is the set of lowercase letters.

Substring, also called factor, is a consecutive sequence of characters occurrences at least once in a string.

Now your task is simple, for two given strings, find the length of the longest common substring of them.

Here common substring means a substring of two or more strings.


The input contains exactly two lines, each line consists of no more than 250000 lowercase letters, representing a string.


The length of the longest common substring. If such string doesn't exist, print "0" instead.




Notice: new testcases added

Added by:Bin Jin
Time limit:0.294s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel Pentium G860 3GHz)
Languages:All except: C++ 5

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(Tjandra Satria Gunawan)(曾毅昆): 2015-08-21 17:53:02

Optimized Suffix Array -> TLE
Unoptomized Ukkonen -> AC (it's hard for me, need 1 day to understand the concept + 1 day to implement & debug it)
I'm tired but satisfied with this problem ;-)

Omer Farukh: 2015-03-14 19:37:04

Is the answer for given testcase correct ?
I am getting 8 as answer

Dhruv Mullick: 2015-01-28 12:14:40

nlogn approach gives TLE

Last edit: 2015-01-28 12:15:05
Gaurav Kumar Verma: 2014-10-16 22:11:06

Suffix Automation got AC in C++ but got TLE in JAVA, i dont understand y :(

zicowa: 2014-03-21 18:16:58

geting TLE using suffix array O(nlogn) approach

Terence: 2014-03-20 06:12:57

AC using O(N) suffix array!

knb_dtu: 2014-03-17 11:13:21

Suffix Automation gets AC:)

Chandan Mittal: 2014-01-16 15:55:33

O(NlogN) also TLE

finally!! Suffix Automaton got AC :)

Last edit: 2014-01-18 23:25:00
jimmy: 2013-07-17 07:47:20

O(N*log(N)^2) will result in TLE.

Last edit: 2014-04-09 12:01:26
luyuncheng: 2013-03-15 09:07:25

why I use DC3 TLE who use DC3 AC?could you please talk to me?