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fix: revert ReverseStack deletion and verify linting (#6474) (#6494)

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* fix: revert ReverseStack deletions and ensure lint compliance

* Fix formatting for ReverseStack and test files

* Delete ReverseStackUsingRecursion and its test as requested

---------

Co-authored-by: Deniz Altunkapan <93663085+DenizAltunkapan@users.noreply.github.com>
This commit is contained in:
Vicky
2025-08-22 11:11:36 +05:30
committed by GitHub
parent 3f195c2c89
commit 3961b1dab9
4 changed files with 9 additions and 102 deletions
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3
src/main/java/com/thealgorithms/datastructures/stacks/ReverseStack.java
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@@ -38,6 +38,9 @@ public final class ReverseStack {
* @param stack the stack to reverse; should not be null
*/
public static void reverseStack(Stack<Integer> stack) {
if (stack == null) {
throw new IllegalArgumentException("Stack cannot be null");
}
if (stack.isEmpty()) {
return;
}

44
src/main/java/com/thealgorithms/others/ReverseStackUsingRecursion.java
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@@ -1,44 +0,0 @@
package com.thealgorithms.others;
import java.util.Stack;
/**
* Class that provides methods to reverse a stack using recursion.
*/
public final class ReverseStackUsingRecursion {
private ReverseStackUsingRecursion() {
}
/**
* Reverses the elements of the given stack using recursion.
*
* @param stack the stack to be reversed
* @throws IllegalArgumentException if the stack is null
*/
public static void reverse(Stack<Integer> stack) {
if (stack == null) {
throw new IllegalArgumentException("Stack cannot be null");
}
if (!stack.isEmpty()) {
int topElement = stack.pop();
reverse(stack);
insertAtBottom(stack, topElement);
}
}
/**
* Inserts an element at the bottom of the given stack.
*
* @param stack the stack where the element will be inserted
* @param element the element to be inserted at the bottom
*/
private static void insertAtBottom(Stack<Integer> stack, int element) {
if (stack.isEmpty()) {
stack.push(element);
} else {
int topElement = stack.pop();
insertAtBottom(stack, element);
stack.push(topElement);
}
}
}

6
src/test/java/com/thealgorithms/datastructures/stacks/ReverseStackTest.java
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@@ -1,6 +1,7 @@
package com.thealgorithms.datastructures.stacks;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;
import java.util.Stack;
@@ -8,6 +9,11 @@ import org.junit.jupiter.api.Test;
class ReverseStackTest {
@Test
void testReverseNullStack() {
assertThrows(IllegalArgumentException.class, () -> ReverseStack.reverseStack(null), "Reversing a null stack should throw an IllegalArgumentException.");
}
@Test
void testReverseEmptyStack() {
Stack<Integer> stack = new Stack<>();

58
src/test/java/com/thealgorithms/others/ReverseStackUsingRecursionTest.java
View File

@@ -1,58 +0,0 @@
package com.thealgorithms.others;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;
import java.util.Stack;
import org.junit.jupiter.api.Test;
public class ReverseStackUsingRecursionTest {
@Test
void testReverseWithMultipleElements() {
Stack<Integer> stack = new Stack<>();
for (int i = 0; i < 5; i++) {
stack.push(i);
}
ReverseStackUsingRecursion.reverse(stack);
for (int i = 0; i < 5; i++) {
assertEquals(i, stack.pop());
}
assertTrue(stack.isEmpty());
}
@Test
void testReverseWithSingleElement() {
Stack<Integer> stack = new Stack<>();
stack.push(1);
ReverseStackUsingRecursion.reverse(stack);
assertEquals(1, stack.pop());
assertTrue(stack.isEmpty());
}
@Test
void testReverseWithEmptyStack() {
Stack<Integer> stack = new Stack<>();
ReverseStackUsingRecursion.reverse(stack);
assertTrue(stack.isEmpty());
}
@Test
void testReverseWithNullStack() {
Stack<Integer> stack = null;
Exception exception = assertThrows(IllegalArgumentException.class, () -> ReverseStackUsingRecursion.reverse(stack));
String expectedMessage = "Stack cannot be null";
String actualMessage = exception.getMessage();
assertTrue(actualMessage.contains(expectedMessage));
}
}