Created Longest-Common-Substring.java

All Algorithms/Dynamic Programming/LIS/Longest-Common-Substring.java

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+public class LongestCommonSubstring {
+    public static String findLongestCommonSubstring(String str1, String str2) {
+        int m = str1.length();
+        int n = str2.length();
+
+        // Create a 2D table to store the lengths of common substrings
+        int[][] dp = new int[m + 1][n + 1];
+
+        // To store the length of the longest common substring found so far
+        int maxLength = 0;
+
+        // To store the ending position of the longest common substring found so far
+        int endIndex = 0;
+
+        // Fill the dp table
+        for (int i = 1; i <= m; i++) {
+            for (int j = 1; j <= n; j++) {
+                if (str1.charAt(i - 1) == str2.charAt(j - 1)) {
+                    dp[i][j] = dp[i - 1][j - 1] + 1;
+                    if (dp[i][j] > maxLength) {
+                        maxLength = dp[i][j];
+                        endIndex = i;
+                    }
+                } else {
+                    dp[i][j] = 0;
+                }
+            }
+        }
+
+        // Extract the longest common substring using endIndex and maxLength
+        String longestCommonSubstring = str1.substring(endIndex - maxLength, endIndex);
+        return longestCommonSubstring;
+    }
+
+    public static void main(String[] args) {
+        String str1 = "ABABC";
+        String str2 = "BABC";
+
+        String lcs = findLongestCommonSubstring(str1, str2);
+        System.out.println("Longest Common Substring: " + lcs); // Output: "BABC"
+    }
+}