A Circular Queue (also known as a Ring Buffer) is a linear data structure where the last position is connected back to the first position to make a circle. This resolves the major limitation of a normal Queue where space is lost once an element is dequeued.
class CircularQueue:
def __init__(self, k: int):
self.k = k
self.q = [None] * k
self.head = self.tail = -1
def enQueue(self, value: int) -> bool:
if self.isFull(): return False
if self.isEmpty(): self.head = 0
self.tail = (self.tail + 1) % self.k
self.q[self.tail] = value
return True
def deQueue(self) -> bool:
if self.isEmpty(): return False
if self.head == self.tail:
self.head = self.tail = -1
else:
self.head = (self.head + 1) % self.k
return Trueclass CircularQueue {
constructor(k) {
this.q = new Array(k);
this.k = k;
this.head = -1;
this.tail = -1;
}
enQueue(value) {
if (this.isFull()) return false;
if (this.isEmpty()) this.head = 0;
this.tail = (this.tail + 1) % this.k;
this.q[this.tail] = value;
return true;
}
deQueue() {
if (this.isEmpty()) return false;
if (this.head === this.tail) {
this.head = this.tail = -1;
} else {
this.head = (this.head + 1) % this.k;
}
return true;
}
}