HackerRank Python Solution - Collections Topic - OrderedDict

An OrderedDict is a dictionary that remembers the order of the keys that were inserted first. If a new entry overwrites an existing entry, the original insertion position is left unchanged.

Example Code:

>>> from collections import OrderedDict
>>> 
>>> ordinary_dictionary = {}
>>> ordinary_dictionary['a'] = 1
>>> ordinary_dictionary['b'] = 2
>>> ordinary_dictionary['c'] = 3
>>> ordinary_dictionary['d'] = 4
>>> ordinary_dictionary['e'] = 5
>>> 
>>> print ordinary_dictionary
{'a': 1, 'c': 3, 'b': 2, 'e': 5, 'd': 4}
>>> 
>>> ordered_dictionary = OrderedDict()
>>> ordered_dictionary['a'] = 1
>>> ordered_dictionary['b'] = 2
>>> ordered_dictionary['c'] = 3
>>> ordered_dictionary['d'] = 4
>>> ordered_dictionary['e'] = 5
>>> 
>>> print ordered_dictionary
OrderedDict([('a', 1), ('b', 2), ('c', 3), ('d', 4), ('e', 5)])

Task:

• You are the manager of a supermarket.

• You have a list of N items together with their prices that consumers bought on a particular day.

• Your task is to print each item_name and net_price in order of its first occurrence.

• item_name = Name of the item.

• net_price = quantity of the item sold multiplied by the price of each item.

Input Format:

• The first line contains the number of items, N.

• The next N lines contain the item's name and price, separated by a space.

Constraints:

• 0 < N <= 100

Output Format:

Print the item_name and net_price in order of its first occurrence.

Sample Input:

9
BANANA FRIES 12
POTATO CHIPS 30
APPLE JUICE 10
CANDY 5
APPLE JUICE 10
CANDY 5
CANDY 5
CANDY 5
POTATO CHIPS 30

Sample Output:

BANANA FRIES 12
POTATO CHIPS 60
APPLE JUICE 20
CANDY 20

Explanation:

• BANANA FRIES: Quantity bought: 1, Price: 12
• Net Price: 12

• POTATO CHIPS: Quantity bought: 2, Price: 30
• Net Price: 60

• APPLE JUICE: Quantity bought: 2, Price: 10
• Net Price: 20

• CANDY: Quantity bought: 4, Price: 5
• Net Price: 20

Solution:

from collections import OrderedDict

N = int(input())

itemDict = OrderedDict()

for _ in range(N):
    
    item = input().split()    
    if len(item) > 2:
        item_name = item[0] + ' ' + item[1]
        item_price = int(item[2])
    else:
        item_name = item[0]
        item_price = int(item[1])
        
    #update the itemDict ordered dictionary
    if (item_name in itemDict):
        curPrice = itemDict[item_name] + item_price
        itemDict[item_name] = curPrice
    else:
        itemDict[item_name] = item_price

print(*[ " ".join((item, str(price))) for item,price in itemDict.items()],sep='\n')
            

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