LongestCommonSubsequence.java

public class LongestCommonSubsequence {
    public static void main(String[] args) {
        String str1 = "AGGTAB";
        String str2 = "GXTXAYB";
        System.out.println("Length of Longest Common Subsequence between \"" + str1 + "\" and \"" + str2 + "\" is: " + lcs(str1, str2));
    }

    public static int lcs(String str1, String str2) {
        int m = str1.length();
        int n = str2.length();
        int[][] dp = new int[m + 1][n + 1];

        for (int i = 0; i <= m; i++) {
            for (int j = 0; j <= n; j++) {
                if (i == 0 || j == 0) {
                    dp[i][j] = 0; // Base case: one string is empty
                } else if (str1.charAt(i - 1) == str2.charAt(j - 1)) {
                    dp[i][j] = dp[i - 1][j - 1] + 1; // Characters match
                } else {
                    dp[i][j] = Math.max(dp[i - 1][j], dp[i][j - 1]); // Characters don't match
                }
            }
        }
        return dp[m][n];
    }
}