Implement saddleback search

src/main/java/com/search/SaddlebackSearch.java

@@ -0,0 +1,46 @@
+package com.search;
+
+/**
+ * Saddleback search is an algorithm which finds the position of a target value within a 2D sorted array
+ */
+public class SaddlebackSearch {
+
+    /**
+     * This method performs Saddleback Search
+     *
+     * @param array The **Sorted** array in which we will search the element.
+     * @param value the element that we want to search for.
+     * @return The index (row and column) of the element if found.
+     * Else returns -1 -1.
+     */
+    public static <T extends Comparable<T>> int[] find(T[][] array, T value) {
+        return search(array, value, array.length - 1, 0);
+    }
+
+    /**
+     * This method performs Saddleback Search
+     *
+     * @param array The **Sorted** array in which we will search the element.
+     * @param value the element that we want to search for.
+     * @param row the current row.
+     * @param col the current column.
+     * @return The index (row and column) of the element if found.
+     * Else returns -1 -1.
+     */
+    private static <T extends Comparable<T>> int[] search(T[][] array, T value, int row, int col) {
+        if (row < 0 || col >= array[row].length) {
+            return new int[] {-1, -1};
+        }
+
+        int compareTo = array[row][col].compareTo(value);
+
+        if (compareTo == 0) {
+            return new int[] {row, col};
+        } else if (compareTo > 0) {
+            return search(array, value, row - 1, col);
+        }
+
+        return search(array, value, row, col + 1);
+    }
+
+}

src/test/java/com/search/SaddlebackSearchTest.java

@@ -0,0 +1,36 @@
+package com.search;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class SaddlebackSearchTest {
+
+    @Test
+    void testBinarySearch() {
+        Integer[][] arr1 = {
+            {1, 2, 3, 4, 5},
+            {6, 7, 8, 9, 10},
+            {11, 12, 13, 14, 15},
+            {16, 17, 18, 19, 20},
+        };
+
+        Assertions.assertArrayEquals(new int[] {1, 0}, SaddlebackSearch.find(arr1, 6), "Incorrect index");
+        Assertions.assertArrayEquals(new int[] {1, 4}, SaddlebackSearch.find(arr1, 10), "Incorrect index");
+        Assertions.assertArrayEquals(new int[] {3, 4}, SaddlebackSearch.find(arr1, 20), "Incorrect index");
+        Assertions.assertArrayEquals(new int[] {0, 0}, SaddlebackSearch.find(arr1, 1), "Incorrect index");
+        Assertions.assertArrayEquals(new int[] {-1, -1}, SaddlebackSearch.find(arr1, -10), "Incorrect index");
+
+        String[][] arr2 = {
+                {"A", "B", "C", "D", "E"},
+                {"F", "G", "H", "I", "J"},
+                {"K", "L", "M", "N", "O"},
+        };
+
+        Assertions.assertArrayEquals(new int[] {1, 0}, SaddlebackSearch.find(arr2, "F"), "Incorrect index");
+        Assertions.assertArrayEquals(new int[] {1, 4}, SaddlebackSearch.find(arr2, "J"), "Incorrect index");
+        Assertions.assertArrayEquals(new int[] {2, 4}, SaddlebackSearch.find(arr2, "O"), "Incorrect index");
+        Assertions.assertArrayEquals(new int[] {0, 0}, SaddlebackSearch.find(arr2, "A"), "Incorrect index");
+        Assertions.assertArrayEquals(new int[] {-1, -1}, SaddlebackSearch.find(arr2, "X"), "Incorrect index");
+    }
+
+}