点菜表示法

2021-07-06

1418. 点菜展示表

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给你一个数组 orders，表示客户在餐厅中完成的订单，确切地说， orders[i]=[customerNamei,tableNumberi,foodItemi] ，其中 customerNamei 是客户的姓名，tableNumberi 是客户所在餐桌的桌号，而 foodItemi 是客户点的餐品名称。

请你返回该餐厅的 点菜展示表 。在这张表中，表中第一行为标题，其第一列为餐桌桌号 “Table” ，后面每一列都是按字母顺序排列的餐品名称。接下来每一行中的项则表示每张餐桌订购的相应餐品数量，第一列应当填对应的桌号，后面依次填写下单的餐品数量。

注意：客户姓名不是点菜展示表的一部分。此外，表中的数据行应该按餐桌桌号升序排列。

示例 1：

输入：orders = [["David","3","Ceviche"],["Corina","10","Beef Burrito"],["David","3","Fried Chicken"],["Carla","5","Water"],["Carla","5","Ceviche"],["Rous","3","Ceviche"]]
输出：[["Table","Beef Burrito","Ceviche","Fried Chicken","Water"],["3","0","2","1","0"],["5","0","1","0","1"],["10","1","0","0","0"]] 
解释：
点菜展示表如下所示：
Table,Beef Burrito,Ceviche,Fried Chicken,Water
3    ,0           ,2      ,1            ,0
5    ,0           ,1      ,0            ,1
10   ,1           ,0      ,0            ,0
对于餐桌 3：David 点了 "Ceviche" 和 "Fried Chicken"，而 Rous 点了 "Ceviche"
而餐桌 5：Carla 点了 "Water" 和 "Ceviche"
餐桌 10：Corina 点了 "Beef Burrito"

示例 2：

输入：orders = [["James","12","Fried Chicken"],["Ratesh","12","Fried Chicken"],["Amadeus","12","Fried Chicken"],["Adam","1","Canadian Waffles"],["Brianna","1","Canadian Waffles"]]
输出：[["Table","Canadian Waffles","Fried Chicken"],["1","2","0"],["12","0","3"]] 
解释：
对于餐桌 1：Adam 和 Brianna 都点了 "Canadian Waffles"
而餐桌 12：James, Ratesh 和 Amadeus 都点了 "Fried Chicken"

示例 3：

1 2	输入：orders = [["Laura","2","Bean Burrito"],["Jhon","2","Beef Burrito"],["Melissa","2","Soda"]] 输出：[["Table","Bean Burrito","Beef Burrito","Soda"],["2","1","1","1"]]

提示：

1 <= orders.length <= 5 * 10^4
orders[i].length == 3
1 <= customerNamei.length, foodItemi.length <= 20
customerNamei 和 foodItemi 由大小写英文字母及空格字符 ' ' 组成。
tableNumberi 是 1 到 500 范围内的整数。


class Solution {
    public List<List<String>> displayTable(List<List<String>> orders) {
        // 从订单中获取餐品名称和桌号，统计每桌点餐数量
        Set<String> nameSet = new HashSet<String>();
        Map<Integer, Map<String, Integer>> foodsCnt = new HashMap<Integer, Map<String, Integer>>();
        for (List<String> order : orders) {
            nameSet.add(order.get(2));
            int id = Integer.parseInt(order.get(1));
            Map<String, Integer> map = foodsCnt.getOrDefault(id, new HashMap<String, Integer>());
            map.put(order.get(2), map.getOrDefault(order.get(2), 0) + 1);
            foodsCnt.put(id, map);
        }

        // 提取餐品名称，并按字母顺序排列
        int n = nameSet.size();
        List<String> names = new ArrayList<String>();
        for (String name : nameSet) {
            names.add(name);
        }
        Collections.sort(names);

        // 提取桌号，并按餐桌桌号升序排列
        int m = foodsCnt.size();
        List<Integer> ids = new ArrayList<Integer>();
        for (int id : foodsCnt.keySet()) {
            ids.add(id);
        }
        Collections.sort(ids);

        // 填写点菜展示表
        List<List<String>> table = new ArrayList<List<String>>();
        List<String> header = new ArrayList<String>();
        header.add("Table");
        for (String name : names) {
            header.add(name);
        }
        table.add(header);
        for (int i = 0; i < m; ++i) {
            int id = ids.get(i);
            Map<String, Integer> cnt = foodsCnt.get(id);
            List<String> row = new ArrayList<String>();
            row.add(Integer.toString(id));
            for (int j = 0; j < n; ++j) {
                row.add(Integer.toString(cnt.getOrDefault(names.get(j), 0)));
            }
            table.add(row);
        }
        return table;
    }
}