46. 멀티 태스킹 (카카오 "먹방" 문제 변형)

나의정답.

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <string>
#include <algorithm>
#include <vector>

using namespace std;

class Node {
public:
	int data;
	int pos;
	Node* Next;
	Node* Prev;
};

class CircularLinkedList {
public:
	Node* Head = NULL;
	Node* Tail = NULL;
	int Count = 0;

	Node* AddLast(int data) {
		Node* newRoom = new Node();
		newRoom->data = data;

		if (Head == NULL) {
			newRoom->pos = 0;
			Head = newRoom;
			Head->Next = newRoom;
			Head->Prev = newRoom;
		}

		if (Tail != NULL) {
			Tail->Next = newRoom;
			newRoom->Prev = Tail;
		}
		Tail = newRoom;
		Tail->Next = Head;
		newRoom->pos = newRoom->Prev->pos + 1;
		Count++;

		return newRoom;
	}
	
	void Remove(Node* node) {
		if (node == Head) {
			Head = Head->Next;
			Tail->Next = Head;
		}

		if (node == Tail) {
			Tail = Tail->Prev;
		}

		if(node->Prev != NULL)
			node->Prev->Next = node->Next;

		if (node->Next != NULL)
			node->Next->Prev = node->Prev;

		Count--;
	}
};

int main(int argc, char** argv) {
	//freopen("input.txt", "rt", stdin);
	
	int n, k, tmp;
	CircularLinkedList* a = new CircularLinkedList();
	Node* curr;

	cin >> n;

	for (int i = 0; i < n; i++) {
		cin >> tmp;
		a->AddLast(tmp);
	}

	cin >> k;
	curr = a->Head;
	while (k > 0) {
		curr->data--;
		if (curr->data == 0)
			a->Remove(curr);
		curr = curr->Next;
		tmp = curr->pos;
		k--;
	}

	if (a->Count > 0)
		cout << tmp;
	else
		cout << -1;

	delete a;
	delete curr;
}