From e638b4218d65e50910ed43012219fc078c47668b Mon Sep 17 00:00:00 2001
From: Hardik Kaurani <hardikkaurani1@gmail.com>
Date: Mon, 2 Nov 2026 11:30:03 +0530
Subject: [PATCH] fix(searches): add null safety and empty matrix handling to
 RowColumnWiseSorted2dArrayBinarySearch

---
 ...owColumnWiseSorted2dArrayBinarySearch.java | 11 +++-
 ...lumnWiseSorted2dArrayBinarySearchTest.java | 56 +++++++++++++++++++
 2 files changed, 66 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearch.java b/src/main/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearch.java
index ecdcd36adf21..940d92d9c382 100644
--- a/src/main/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearch.java
+++ b/src/main/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearch.java
@@ -20,7 +20,7 @@
  * doesn't exist in the array, an array
  * {-1, -1} will be returned.
  */
-public class RowColumnWiseSorted2dArrayBinarySearch implements MatrixSearchAlgorithm {
+public final class RowColumnWiseSorted2dArrayBinarySearch implements MatrixSearchAlgorithm {
 
     @Override
     public <T extends Comparable<T>> int[] find(T[][] matrix, T key) {
@@ -28,10 +28,19 @@ public <T extends Comparable<T>> int[] find(T[][] matrix, T key) {
     }
 
     public static <T extends Comparable<T>> int[] search(T[][] matrix, T target) {
+        if (matrix == null || matrix.length == 0 || matrix[0] == null || matrix[0].length == 0 || target == null) {
+            return new int[] {-1, -1};
+        }
+
         int rowPointer = 0; // The pointer at 0th row
         int colPointer = matrix[0].length - 1; // The pointer at end column
 
         while (rowPointer < matrix.length && colPointer >= 0) {
+            if (matrix[rowPointer] == null || colPointer >= matrix[rowPointer].length) {
+                rowPointer++;
+                continue;
+            }
+
             int comp = target.compareTo(matrix[rowPointer][colPointer]);
 
             if (comp == 0) {
diff --git a/src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java b/src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java
index 8d1423cbeeb0..9259f57941a7 100644
--- a/src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java
+++ b/src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java
@@ -237,4 +237,60 @@ public void rowColumnSorted2dArrayBinarySearchTestTallMatrixNotFound() {
         assertEquals(expected[0], ans[0]);
         assertEquals(expected[1], ans[1]);
     }
+
+    @Test
+    public void testNullMatrixReturnsNotFound() {
+        int[] ans = RowColumnWiseSorted2dArrayBinarySearch.search(null, 5);
+        int[] expected = {-1, -1};
+        assertEquals(expected[0], ans[0]);
+        assertEquals(expected[1], ans[1]);
+    }
+
+    @Test
+    public void testEmptyMatrixReturnsNotFound() {
+        Integer[][] matrix = {};
+        int[] ans = RowColumnWiseSorted2dArrayBinarySearch.search(matrix, 5);
+        int[] expected = {-1, -1};
+        assertEquals(expected[0], ans[0]);
+        assertEquals(expected[1], ans[1]);
+    }
+
+    @Test
+    public void testEmptyFirstRowReturnsNotFound() {
+        Integer[][] matrix = {{}};
+        int[] ans = RowColumnWiseSorted2dArrayBinarySearch.search(matrix, 5);
+        int[] expected = {-1, -1};
+        assertEquals(expected[0], ans[0]);
+        assertEquals(expected[1], ans[1]);
+    }
+
+    @Test
+    public void testNullTargetReturnsNotFound() {
+        int[] ans = RowColumnWiseSorted2dArrayBinarySearch.search(WIDE_RECTANGULAR_MATRIX, null);
+        int[] expected = {-1, -1};
+        assertEquals(expected[0], ans[0]);
+        assertEquals(expected[1], ans[1]);
+    }
+
+    @Test
+    public void testMatrixWithNullRow() {
+        Integer[][] matrix = {
+            {10, 20, 30},
+            null,
+            {18, 28, 38},
+        };
+        int[] ans = RowColumnWiseSorted2dArrayBinarySearch.search(matrix, 28);
+        int[] expected = {2, 1};
+        assertEquals(expected[0], ans[0]);
+        assertEquals(expected[1], ans[1]);
+    }
+
+    @Test
+    public void testFindMethodThroughInterface() {
+        RowColumnWiseSorted2dArrayBinarySearch searcher = new RowColumnWiseSorted2dArrayBinarySearch();
+        int[] ans = searcher.find(WIDE_RECTANGULAR_MATRIX, 35);
+        int[] expected = {1, 2};
+        assertEquals(expected[0], ans[0]);
+        assertEquals(expected[1], ans[1]);
+    }
 }