leetcode 1418. Display Table of Food Orders in a Restaurant （python）

「 This is my participation 11 The fourth of the yuegengwen challenge 15 God , Check out the activity details ：2021 One last more challenge 」

describe

Given the array orders, which represents the orders that customers have done in a restaurant. More specifically orders[i]=[customerName_i,tableNumber_i,foodItem_i] where customerName_i is the name of the customer, tableNumber_i is the table customer sit at, and foodItem_i is the item customer orders.

Return the restaurant's “display table”. The “display table” is a table whose row entries denote how many of each food item each table ordered. The first column is the table number and the remaining columns correspond to each food item in alphabetical order. The first row should be a header whose first column is “Table”, followed by the names of the food items. Note that the customer names are not part of the table. Additionally, the rows should be sorted in numerically increasing order.

Example 1:

Input: orders = [["David","3","Ceviche"],["Corina","10","Beef Burrito"],["David","3","Fried Chicken"],["Carla","5","Water"],["Carla","5","Ceviche"],["Rous","3","Ceviche"]]
Output: [["Table","Beef Burrito","Ceviche","Fried Chicken","Water"],["3","0","2","1","0"],["5","0","1","0","1"],["10","1","0","0","0"]] 
Explanation:
The displaying table looks like:
Table,Beef Burrito,Ceviche,Fried Chicken,Water
3    ,0           ,2      ,1            ,0
5    ,0           ,1      ,0            ,1
10   ,1           ,0      ,0            ,0
For the table 3: David orders "Ceviche" and "Fried Chicken", and Rous orders "Ceviche".
For the table 5: Carla orders "Water" and "Ceviche".
For the table 10: Corina orders "Beef Burrito". 
 Copy code 

Example 2:

Input: orders = [["James","12","Fried Chicken"],["Ratesh","12","Fried Chicken"],["Amadeus","12","Fried Chicken"],["Adam","1","Canadian Waffles"],["Brianna","1","Canadian Waffles"]]
Output: [["Table","Canadian Waffles","Fried Chicken"],["1","2","0"],["12","0","3"]] 
Explanation: 
For the table 1: Adam and Brianna order "Canadian Waffles".
For the table 12: James, Ratesh and Amadeus order "Fried Chicken".
 Copy code 

Example 3:

Input: orders = [["Laura","2","Bean Burrito"],["Jhon","2","Beef Burrito"],["Melissa","2","Soda"]]
Output: [["Table","Bean Burrito","Beef Burrito","Soda"],["2","1","1","1"]]
 Copy code 

Note:

• 1 <= orders.length <= 5 * 10^4
• orders[i].length == 3
• 1 <= customerNamei.length, foodItemi.length <= 20
• customerNamei and foodItemi consist of lowercase and uppercase English letters and the space character.
• tableNumber_i is a valid integer between 1 and 500.

analysis

According to the meaning , Given array orders, It represents the order placed by the customer in the restaurant . orders[i]=[customerName_i,tableNumber_i,foodItem_i] among customerName_i It's the customer's name ,tableNumber_i It's the customer's table ,foodItem_i It is the item of the customer's order .

The title asks us to return to a restaurant “display table”. “display table” Is a table , The first line is a header , The first column is “ Table ”, The remaining columns are alphabetical for each food item . Starting from the second line, it shows the quantity of each food ordered per table . It should be noted that the customer name is not part of the table . In addition, the rows should be sorted in ascending order of table number .

It seems that the topic is more complicated , In fact, the customer name is useless , The key depends on the table number and dish name , After reading the example, you can basically know the requirements of the topic , The idea is also simple ：

• Initialize empty list result Show the result , Initialize empty list head Indicates the header , Initialize empty dictionary d Indicates the dishes and quantity corresponding to each table number
• Traverse all orders orders , use d Record the table number and its corresponding dishes and quantity , And put the dish name into head in
• The end of traversal will head Arrange in dictionary order and put ‘Table’ The string is inserted to the front to form the final header , And will head Append to result in
• To the dictionary d Sort by table number in ascending order , Then traverse d The key/value pair , according to head[1:] The order of Chinese dishes , Add the dishes of each table number and their quantity to the new list row in , And will row Append to result in
• Return after traversal result that will do

answer

class Solution(object):
    def displayTable(self, orders):
        """
        :type orders: List[List[str]]
        :rtype: List[List[str]]
        """
        result = []
        head = []
        d = {}
        for order in orders:
            if order[1] not in d:
                d[order[1]] = {}
            if order[2] not in d[order[1]]:
                d[order[1]][order[2]] = 1
            else:
                d[order[1]][order[2]] += 1
            if order[2] not in head:
                head.append(order[2])
        head.sort()
        head = ['Table'] + head
        result.append(head)
        d = sorted(d.items(), key=lambda d: int(d[0]))
        for k, v in d:
            row = [k]
            for food in head[1:]:
                if food not in v:
                    row.append('0')
                else:
                    row.append(str(v[food]))
            result.append(row)
        return result
        
        	      
		
 Copy code 

Running results

Runtime: 400 ms, faster than 94.12% of Python online submissions for Display Table of Food Orders in a Restaurant.
Memory Usage: 22.9 MB, less than 47.06% of Python online submissions for Display Table of Food Orders in a Restaurant.
 Copy code 

Original link ：leetcode.com/problems/di…

Your support is my greatest motivation