Lintcode Longest Common Substring

The original title link is here: http://www.lintcode.com/en/problem/longest-common-substring/#

Topic:

Given, strings, find the longest common substring.

Return the length of it.

The characters in substringShould occur continuously in original string. This was different with subsequence. Example

Given A = "ABCD" , B = "CBCE" , return 2 . "BC"

Challenge

O (n x m) time and memory.

Exercises

Similar to longest Common subsequence.

Dp. Reference http://www.geeksforgeeks.org/longest-common-substring/

DP[I][J] Represents the length of the str1 of I and str2 longest common substring of length J.

Look at the suffix of two substring.

DP[I][J] = dp[i-1][j-1] + 1 if Str1.charat (i-1) = = Str2.charat (j-1).

DP[I][J] = 0. O.w

Time Complexity:o (m*n). Space:o (m*n).

AC Java:

1  Public classSolution {2     /**3      * @paramA, b:two string.4      * @return: The length of the longest common substring.5      */6      Public intlongestcommonsubstring (String A, String B) {7         if(A = =NULL|| B = =NULL){8             return0;9         }Ten         intm =a.length (); One         intn =b.length (); A         int[] DP =New int[M+1] [N+1]; -         intLongest = 0; -          for(inti = 1; i<=m; i++){ the              for(intj = 1; j<=n; J + +){ -                 if(A.charat (i-1) = = B.charat (j-1)){ -DP[I][J] = dp[i-1][j-1]+1; -}Else{ +DP[I][J] = 0; -                 } +Longest =Math.max (Longest, dp[i][j]); A             } at         } -         returnlongest; -     } -}

Lintcode Longest Common Substring