Untitled

package SoldierManagement;

class UserSolution {
	class Node // Soldier Node
	{
		int id, team, score;
		Node prev, next;

		Node(int id, int team) {
			this.id = id;
			this.team = team;
			this.prev = null;
			this.next = null;
		}

		Node(int id, int team, int score) {
			this.id = id;
			this.team = team;
			this.score = score;

			this.prev = null;
			this.next = null;
		}
	}

	// 1D Array to Store soldiers id: 1, 100000
	public static int MAX_N = 100001;
	Node[] pool = new Node[MAX_N];

	// 2D-Array of Double LinkedList Nodes
	// Mảng 2 chiều quản lý các lính khác ID thuộc cùng một đội và điểm số
	Node[][] teams = new Node[6][6];

	public void init() {
		// System.out.println("Init Called:");
		// Add Dummy nodes (các nút giả) in the DLL
		for (int i = 1; i <= 5; i++) {
			for (int j = 1; j <= 5; j++) {
				// teams[team][score] => (Head Node)
				teams[i][j] = new Node(-1, -1);
				teams[i][j].next = teams[i][j]; // point next of dummy to self
				teams[i][j].prev = teams[i][j]; // point prev of dummy to self
			}
		}
		return;
	}

	public void hire(int mId, int mTeam, int mScore) {
		// System.out.println("Hire Called:");

		// 1. Create node - id độc nhất, kèm theo đội mà lính thuộc về
		pool[mId] = new Node(mId, mTeam);

		// 2. Add Node to memory pool (thêm vào bộ nhớ)
		Node node = pool[mId]; // cả prev và next đều là null

		// 3. Add Node to teams[team][score]
		Node head = teams[mTeam][mScore];
		node.prev = head.prev;
		node.next = head;
		// cập nhật node trước node được thêm, next của nó không phải là head
		// nữa mà là node mới
		head.prev.next = node;
		// cập nhật node giả
		head.prev = node;
		return;
	}

	public void fire(int mId) {
		// System.out.println("Fire Called:");

		// 1. Get Node
		Node node = pool[mId];

		// 2. Update next & prev => Easy deletion
		node.prev.next = node.next;
		node.next.prev = node.prev;
		return;
	}

	public void updateSoldier(int mId, int mScore) {
		// System.out.println("Update Soldier Called:");

		// 1. Get Node
		Node node = pool[mId];

		// 2. Delete node from team & prev ** score
		fire(mId);

		// 3. Add Node again in team & new ** score
		hire(mId, node.team, mScore);

		return;
	}

	public void updateTeam(int mTeam, int mChangeScore) {
		// System.out.println("Update Team Called:");

		if (mChangeScore < 0) // Score decreases
		{
			for (int i = 1; i <= 5; i++) {
				int new_score = i + mChangeScore;

				if (new_score < 1)
					new_score = 1;

				if (new_score != i) // we need to move lists
				{
					Node old_head = teams[mTeam][i];
					Node new_head = teams[mTeam][new_score];

					// Next of last node in old list
					// vì old_head.prev chính là last node
					old_head.prev.next = new_head.next;
					// first of new points to last of old
					new_head.next.prev = old_head.prev;

					new_head.next = old_head.next;
					new_head.next.prev = new_head;

					// Reset List
					old_head.next = old_head;
					old_head.prev = old_head;
				}
			}
		} else // Score increases
		{
			for (int i = 5; i >= 1; i--) {
				int new_score = i + mChangeScore;

				if (new_score > 5)
					new_score = 5;

				if (new_score < 1)
					new_score = 1;

				if (new_score != i) // we need to move lists
				{
					Node old_head = teams[mTeam][i];
					Node new_head = teams[mTeam][new_score];

					// Next of last node in old list
					old_head.prev.next = new_head.next;
					new_head.next.prev = old_head.prev; // first of new points
														// to last of old

					new_head.next = old_head.next;
					new_head.next.prev = new_head;

					// Reset List
					old_head.next = old_head;
					old_head.prev = old_head;
				}
			}
		}

		return;
	}

	public int bestSoldier(int mTeam) {
		// System.out.println("Best Soldier Called:");

		int max = 0;

		// 1. Traverse over all scores for the given team
		// In reverse order because we need soldier with highest score & highest
		// id
		for (int i = 5; i >= 1; i--) {
			Node head = teams[mTeam][i];
			if (head.next != head) // When the list is not empty
			{
				Node temp;
				temp = head.next; // pointer to traverse list
				while (temp != head) {
					if (temp.id > max) // update max
						max = temp.id;

					temp = temp.next; // move to next
				}

				// after this lists only with less score will be present
				// So if this list was not empty & we found a max
				// That max is the only possible max
				break;
			}
		}
		return max;
	}
}