点菜展示表

[yankewei]

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：

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。

来源：力扣（LeetCode）
链接：https://leetcode-cn.com/problems/display-table-of-food-orders-in-a-restaurant
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[yankewei]

哈希表

go语言的map没有php的数据方便，哈哈，但是要注意返回类型，必须是string

class Solution {

    /**
     * @param String[][] $orders
     * @return String[][]
     */
    function displayTable($orders) {
        $ret = [['Table']];
        // 保存所有的餐品
        $foods = [];
        // 保存所有的桌号
        $tables = [];
        // 生成一个嵌套数据，数据key是桌号，value是一个数组，value的key是餐品名称，value的value是餐品数量
        $cntByFoodByTable = [];
        foreach ($orders as $order) {
            if (isset($cntByFoodByTable[$order[1]])) {
                $cntByFood = $cntByFoodByTable[$order[1]];
                if (isset($cntByFood[$order[2]])) {
                    $cntByFood[$order[2]] = $cntByFood[$order[2]] + 1;
                } else {
                    $cntByFood[$order[2]] = 1;
                }
                $cntByFoodByTable[$order[1]] = $cntByFood;
            } else {
                $cntByFoodByTable[$order[1]][$order[2]] = 1;
            }
            $foods[] = $order[2];
            $tables[] = $order[1];
        }
        $foods = array_unique($foods);
        sort($foods);
        $tables = array_unique($tables);
        sort($tables);

        foreach ($foods as $food) {
            $ret[0][] = $food;
        }
        foreach ($tables as $table) {
            $row = [];
            $row[] = $table;
            foreach ($foods as $food) {
                $row[] = isset($cntByFoodByTable[$table][$food]) ? $cntByFoodByTable[$table][$food] : 0;
            }
            $ret[] = $row;
        }
        return $ret;
    }
}