Ring Bufferの実装
code:solution.cpp
class MyCircularQueue {
public:
vector<int> vec = {};
int head = -1;
int tail = -1;
/** Initialize your data structure here. Set the size of the queue to be k. */
MyCircularQueue(int k) {
vec.resize(k);
}
/** Insert an element into the circular queue. Return true if the operation is successful. */
bool enQueue(int value) {
if (isFull()) return false;
if (isEmpty()) head = 0;
tail = next(tail);
return true;
}
/** Delete an element from the circular queue. Return true if the operation is successful. */
bool deQueue() {
if (isEmpty()) return false;
if (head == tail) {
head = -1;
tail = -1;
return true;
}
head = next(head);
return true;
}
/** Get the front item from the queue. */
int Front() {
if (isEmpty()) return -1;
}
/** Get the last item from the queue. */
int Rear() {
if (isEmpty()) return -1;
}
/** Checks whether the circular queue is empty or not. */
bool isEmpty() {
if (head == -1 && tail == -1) return true;
return false;
}
/** Checks whether the circular queue is full or not. */
bool isFull() {
if (next(tail) == head) return true;
return false;
}
int next(int idx) {
return (idx+1 == vec.size()) ? 0 : idx+1;
}
};
/**
* Your MyCircularQueue object will be instantiated and called as such:
* MyCircularQueue* obj = new MyCircularQueue(k);
* bool param_1 = obj->enQueue(value);
* bool param_2 = obj->deQueue();
* int param_3 = obj->Front();
* int param_4 = obj->Rear();
* bool param_5 = obj->isEmpty();
* bool param_6 = obj->isFull();
*/