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The Captain's Room

Problem link : https://www.hackerrank.com/challenges/py-the-captains-room/problem

Difficulty : Easy

Tip

• Problem description is a bit long
• Point is that captain's room number is appeared only once
• Other room number is repeated
• Create defatultdict with lamda: 0
• room number is a key of dict, and +1 when the number is appeared
• check what key is only appeared one time

Solution

from collections import defaultdict # Enter your code here. Read input from STDIN. Print output to STDOUT k = int(input()) s = list(map(int, input().split(' '))) d = defaultdict(lambda: 0) for i in range(len(s)): d[s[i]] += 1 for k in d.keys(): if d[k] == 1: print(k)