Longest Common Subsequence in C++

Welcome to the Longest Common Subsequence in C++ page! Here, you'll find the source code for this program as well as a description of how the program works.

Current Solution

#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
using namespace std;

vector<string> splitStrings(string str)
{
    string word = "";
    char dl = ',';
    int num = 0;

    str = str + dl;
    int l = str.size();

    vector<string> substr_list;

    for (int i = 0; i < l; i++)
    {
        if (str[i] != dl)
            word = word + str[i];
        else
        {
            if ((int)word.size() != 0)
                substr_list.push_back(word);

            word = "";
        }
    }
    return substr_list;
}

void longest_common_subsequence(vector<string> arr1, vector<string> arr2)
{
    int m = arr1.size();
    int n = arr2.size();
    int table[m + 1][n + 1];

    for (int row = 0; row <= m; row++)
    {
        for (int col = 0; col <= n; col++)
        {

            if (row == 0 || col == 0)
            {
                table[row][col] = 0;
            }
            else if (arr1[row - 1] == arr2[col - 1])
            {
                table[row][col] = 1 + table[row - 1][col - 1];
            }
            else
            {
                table[row][col] = max(table[row][col - 1], table[row - 1][col]);
            }
        }
    }

    vector<string> array_of_lcs;

    int i = m, j = n;
    while (i > 0 && j > 0)
    {
        if (arr1.at(i - 1) == arr2.at(j - 1))
        {
            array_of_lcs.insert(array_of_lcs.begin(), arr2[j - 1]);
            i--;
            j--;
        }
        else
        {
            if (table[i - 1][j] > table[i][j - 1])
            {
                i--;
            }
            else
            {
                j--;
            }
        }
    }

    for (int i = 0; i < array_of_lcs.size() - 1; i++)
    {
        cout << array_of_lcs[i] << ",";
    }
    cout << array_of_lcs[array_of_lcs.size() - 1] << endl;
}

int main(int argc, char *argv[])
{
    if (!(argc > 2 && std::string(argv[1]) != "" && std::string(argv[2]) != ""))
    {
        cout << "Usage: please provide two lists in the format \"1, 2, 3, 4, 5\"" << endl;
        return 1;
    }

    string input1 = argv[1];
    vector<string> arr1 = splitStrings(input1);

    string input2 = argv[2];
    vector<string> arr2 = splitStrings(input2);

    longest_common_subsequence(arr1, arr2);
    return 0;
}

Longest Common Subsequence in C++ was written by:

• Jeremy Grifski
• Shubham Tiwari

If you see anything you'd like to change or update, please consider contributing.

Note: The solution shown above is the current solution in the Sample Programs repository as of Oct 10 2022 16:05:09. The solution was first committed on Oct 13 2019 09:11:38. As a result, documentation below may be outdated.

How to Implement the Solution

No 'How to Implement the Solution' section available. Please consider contributing.

How to Run the Solution

No 'How to Run the Solution' section available. Please consider contributing.