Skip to content

fix(searches): add null safety and empty matrix handling to RowColumnWiseSorted2dArrayBinarySearch #7725

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
hardikkaurani wants to merge 1 commit into
base: master
Choose a base branch
from
Open

fix(searches): add null safety and empty matrix handling to RowColumnWiseSorted2dArrayBinarySearch #7725

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
11 changes: 10 additions & 1 deletion src/main/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearch.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -20,18 +20,27 @@
* 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) {
return search(matrix, 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) {
Expand Down
56 changes: 56 additions & 0 deletions src/test/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearchTest.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -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]);
}
}
Loading