Merge pull request #558 from Ojasvix20/feat/hacktober/Seach2DMatrix

Added search 2D matrix algorithm for hacktober fest

Author: Pradeepsingh61

Java/algorithms/matrix/Search2DMatrix.java

@@ -0,0 +1,91 @@
+/*
+ * Algorithm Name: Search a 2D Matrix
+ * Programming Language: Java
+ * Category: Matrix, Binary Search
+ * Difficulty Level: Medium
+ *
+ * Author: Ojasvi Bakshi
+ *
+ * Algorithm Description:
+ * Efficiently searches for a value in an m x n matrix where each row is sorted
+ * left to right, and the first element of each row is greater than the last
+ * element of the previous row. This implementation uses binary search.
+ *
+ * Time Complexity: O(log(m*n))
+ * Space Complexity: O(1)
+ */
+// package DSA_Code.Java.algorithms.matrix;
+
+import java.util.Scanner;
+import java.util.Arrays;
+
+public class Search2DMatrix {
+
+    public static boolean searchMatrix(int[][] matrix, int target) {
+        if (matrix == null || matrix.length == 0 || matrix[0].length == 0) {
+            return false;
+        }
+
+        int m = matrix.length;
+        int n = matrix[0].length;
+
+        int left = 0;
+        int right = m * n - 1; // Treat the matrix as a flattened 1D array
+
+        while (left <= right) {
+            int mid = left + (right - left) / 2;
+            
+            // Convert the 1D mid-point back to 2D coordinates
+            int midRow = mid / n;
+            int midCol = mid % n;
+            int midValue = matrix[midRow][midCol];
+
+            if (midValue == target) {
+                return true;
+            } else if (midValue < target) {
+                left = mid + 1;
+            } else {
+                right = mid - 1;
+            }
+        }
+
+        return false;
+    }
+
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+
+        System.out.print("Enter number of rows: ");
+        int m = sc.nextInt();
+        System.out.print("Enter number of columns: ");
+        int n = sc.nextInt();
+
+        int[][] matrix = new int[m][n];
+
+        System.out.println("Enter sorted matrix elements:");
+        for (int i = 0; i < m; i++) {
+            for (int j = 0; j < n; j++) {
+                matrix[i][j] = sc.nextInt();
+            }
+        }
+        
+        System.out.print("\nEnter the target value to search for: ");
+        int target = sc.nextInt();
+
+        System.out.println("\nOriginal Matrix:");
+        for (int[] row : matrix) {
+            System.out.println(Arrays.toString(row));
+        }
+
+        // Apply the algorithm
+        boolean found = searchMatrix(matrix, target);
+
+        if (found) {
+            System.out.println("\nTarget " + target + " was found in the matrix. ✅");
+        } else {
+            System.out.println("\nTarget " + target + " was not found in the matrix. ❌");
+        }
+
+        sc.close();
+    }
+}