Find duplicate words in array c#

Question

I have array of subdepartments in deparment. I want return string with combination of subdepartments and department.

public static string[] TestDepartments
        {
            get
            {
                return new string[]
                {
                    "Radio-Electronic Systems and Devices in Radioelectronics and laser technologies department",
                    "Laser and Optic-Electronic Systems in Radioelectronics and laser technologies department",
                    "Optic-Electronic Devices for Scientific Research in Radioelectronics and laser technologies department",
                    "Theoretical Bases of Electrotechnology in Radioelectronics and laser technologies department",
                    "Technologies of Instrument Making in Radioelectronics and laser technologies department"
                };
            }
        }

I need result string:

string result = "Radio-Electronic Systems and Devices, Laser and Optic-Electronic Systems, Optic-Electronic Devices for Scientific Research, Theoretical Bases of Electrotechnology, echnologies of Instrument Making in Radioelectronics and laser technologies department";

What algorithm can you recommend? Or may be exists example for find duplicate word combination in string array? In my example I need find department duplicate. I need universal method for different departments.

@Sayse frankly, it is not a simple join since OP needs to join only subparts of each strings, not a whole strings. — Andrey Korneyev, May 06 '15 at 07:22
@AndyKorneyev - Ah I misread the result string, the rest of my comment still stands however... — Sayse, May 06 '15 at 07:26
@Sayse, I'm tried find subparts of first string and find them in another strings — zrabzdn, May 06 '15 at 07:34
I can't understand what do you expect exactly, a string in which every dep. and subdep. appears only once? — MatteoSp, May 06 '15 at 07:52

score 1 · Accepted Answer · edited May 23 '17 at 12:16

You can start with:

string[] testDepartments = new string[]
{
    "Radio-Electronic Systems and Devices in Radioelectronics and laser technologies department",
    "Laser and Optic-Electronic Systems in Radioelectronics and laser technologies department",
    "Optic-Electronic Devices for Scientific Research in Radioelectronics and laser technologies department",
    "Theoretical Bases of Electrotechnology in Radioelectronics and laser technologies department",
    "Technologies of Instrument Making in Radioelectronics and laser technologies department"
};

int longestCommonPostfixIndex = 0;
string firstString = testDepartments.First();

// TODO: change to binary searching
// TODO: check every string's length
while(testDepartments.All(td => td.Substring(td.Length - longestCommonPostfixIndex) == firstString.Substring(firstString.Length - longestCommonPostfixIndex)))
     longestCommonPostfixIndex++;

string res = string.Join(", ", testDepartments.Select(d => d.Substring(0, d.Length - longestCommonPostfixIndex + 1))) + firstString.Substring(firstString.Length - longestCommonPostfixIndex);

and next try to optimize it.

res = "Radio-Electronic Systems and Devices, Laser and Optic-Electronic Systems, Optic-Electronic Devices for Scientific Research, Theoretical Bases of Electrotechnology, Technologies of Instrument Makings in Radioelectronics and laser technologies department"

You can also look at this: https://stackoverflow.com/a/2070434/3901618 to learn a more fancy way to find the longest common suffix string.

Find duplicate words in array c#

1 Answers1