Every now and then I come across a LeetCode problem that has test cases which contradict the problem statement. One such problem is #622: Design Circular Queue, a medium level problem on LeetCode.
Problem Description: https://leetcode.com/problems/design-circular-queue/
Time Complexity: O(1) across all methods - enqueue, dequeue, front, rear, isEmpty, isFull.
Design:
class MyCircularQueue {
int[] arr;
int front;
int rear;
int size;
public MyCircularQueue(int k) {
arr = new int[k];
front = rear = -1;
size = k;
}
public boolean enQueue(int value) {
if (isFull()) {
// queue is full
return false;
}
if (isEmpty()) {
front = rear = 0;
arr[front] = value;
} else {
rear = (rear+1)%size;
arr[rear] = value;
}
return true;
}
public boolean deQueue() {
if (isEmpty())
return false;
if (front == rear) {
front = rear = -1;
} else {
rear = (rear-1)%size;
}
return true;
}
public int Front() {
if (isEmpty())
return -1;
return arr[front];
}
public int Rear() {
if (isEmpty())
return -1;
return arr[rear];
}
public boolean isEmpty() {
if (front == rear && front == -1) {
// queue is empty
return true;
}
return false;
}
public boolean isFull() {
if (front == (rear+1)%size)
return true;
return false;
}
}
/**
* Your MyCircularQueue object will be instantiated and called as such:
* MyCircularQueue obj = new MyCircularQueue(k);
* boolean param_1 = obj.enQueue(value);
* boolean param_2 = obj.deQueue();
* int param_3 = obj.Front();
* int param_4 = obj.Rear();
* boolean param_5 = obj.isEmpty();
* boolean param_6 = obj.isFull();
*/
Failing test case:
Input
["MyCircularQueue","enQueue","enQueue","enQueue","enQueue","deQueue","deQueue","isEmpty","isEmpty","Rear","Rear","deQueue"]
[[8],[3],[9],[5],[0],[],[],[],[],[],[],[]]
[[8],[3],[9],[5],[0],[],[],[],[],[],[],[]]
Output
[null,true,true,true,true,true,true,false,false,9,9,true]
Expected
[null,true,true,true,true,true,true,false,false,0,0,true]
Dear @LeetCode please remove these erroneous test cases from the problem's test suite.
Happy Coding meanwhile!
