problem
solution
- be careful of pointer out of range
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61class MyCircularDeque {
private:
vector<int> nums;
int cap, front, back;
public:
MyCircularDeque(int k) {
cap = k;
front = back = 0;
nums = vector<int> (k, -1);
}
bool insertFront(int value) {
if(isFull()) return false;
front = (front-1+cap)%cap;
nums[front] = value;
return true;
}
bool insertLast(int value) {
if(isFull()) return false;
nums[back] = value;
back = (back+1)%cap;
return true;
}
bool deleteFront() {
if(isEmpty()) return false;
nums[front] = -1;
front = (front+1)%cap;
return true;
}
bool deleteLast() {
if(isEmpty()) return false;
back = (back-1+cap)%cap;
nums[back] = -1;
return true;
}
int getFront() {
if(isEmpty()) return -1;
return nums[front];
}
int getRear() {
if(isEmpty()) return -1;
return nums[(back-1+cap)%cap];
}
bool isEmpty() {
return nums[front]==-1 && (back==front);
}
bool isFull() {
return nums[front]!=-1 && (back==front);
}
};