To return the longest common Sub-String of two strings

Question

I want a program to return the longest common sub-string of two strings. ex:- if two strings are string str1=Hello how are you string str2=Hello chinni how you doing the output should return 'Hello'(The longest common substring)

Karthikeyan K · Answer

Hi sir using System; namespace LongestCommonSubstring { class Program { static void Main(string[] args) { Console.WriteLine(lcs(Hello how are you Hello chinni how you doing)); Console.ReadKey(true); } public static string lcs(string a string b) { var lengths = new int[a.Length b.Length]; int greatestLength = 0; string output = ; for (int i = 0; i { for (int j = 0; j { if (a[i] == b[j]) { lengths[i j] = i == 0 || j == 0 ? 1 : lengths[i - 1 j - 1] + 1; if (lengths[i j] > greatestLength) { greatestLength = lengths[i j]; output = a.Substring(i - greatestLength + 1 greatestLength); } } else { lengths[i j] = 0; } } } return output; } } }