[数据结构与算法]Java实例：使用集合完成数据存取和排序

要求：考虑存取效率。

package Practice;

import java.util.ArrayList;
import java.util.HashMap;

public class RankMgr {
    private ArrayList<Player> list = new ArrayList<>();
    private HashMap<String, Player> map = new HashMap<>();

    public static void main(String[] args) {
        RankMgr rankMgr = new RankMgr();
        rankMgr.addRank("1001", 22);
        rankMgr.addRank("1001", 1);
        rankMgr.addRank("1001", 1);
        rankMgr.addRank("1001", 1);
        rankMgr.addRank("1002", 10);
        rankMgr.addRank("1002", 33);
        rankMgr.addRank("1002", -10);
        rankMgr.addRank("1002", 10);
        rankMgr.addRank("1001", 10);
        rankMgr.addRank("1001", 10);
        rankMgr.addRank("1001", -10);
        rankMgr.addRank("1001", -10);
        int rank1 = rankMgr.getRank("1001");
        int rank2 = rankMgr.getRank("1002");
    }

    public int addRank(String playerId, int value) {
        // 没有
        // 新生产
        // 比较最后一个,交换
        //交换完设置rank

        // 有
        //通过map,rank找到list索引位置,比较交换
        // 正的，跟前一个交换
        // 负的，后一个交换
        //交换完传索引给rank
        
        if (map.containsKey(playerId)) {

            int index = map.get(playerId).getRank();
            if (value < 0) {
                for (int i = index; i < list.size(); i++) {
                    if (i == list.size() - 1) {
                        if (value < list.get(i).value) {
                            break;
                        } else {
                            list.get(i).value = value;
                        }

                    }
                    Player playerTemp = list.get(i + 1);
                    if (value < playerTemp.value) {

                        Player player = map.get(playerId);
                        list.set(i + 1, player);
                        list.set(i, playerTemp);
                        player.rank = i + 1;
                        playerTemp.rank = i;
                    } else {
                        break;
                    }

                }
            } else {
                for (int i = index; i > 0; i--) {
                    Player playerTemp = list.get(i - 1);
                    if (value > playerTemp.value) {
                        Player player = map.get(playerId);
                        list.set(i - 1, player);
                        list.set(i, playerTemp);
                        player.rank = i - 1;
                        playerTemp.rank = i;
                    } else {
                        break;
                    }
                }
            }


        } else {

            Player player = new Player(playerId, value);
            map.put(playerId, player);
            list.add(player);
            player.rank = list.size() - 1;
            if (list.size() == 1) {
                list.set(0, player);
                player.rank = 0;

            } else {
                for (int i = list.size() - 1; i > 0; i--) {

                    Player playerTemp = list.get(i - 1);
                    if (value > playerTemp.value) {
                        list.set(i - 1, player);
                        list.set(i, playerTemp);
                        player.rank = i - 1;
                        playerTemp.rank = i;
                    } else {

                        break;
                    }
                }
            }
        }

        return 0;
    }

    public int getRank(String playerId) {

        if (map.containsKey(playerId)) {

            System.out.println(playerId + "玩家的排名是No." + map.get(playerId).rank);
        } else {
            System.out.println("排行榜无" + playerId + "玩家");
        }

        return 0;
    }

}