DefaultDict Tutorial HackerRank Solution In Python

Problem

The defaultdict tool is a container in the collections class of Python. It’s similar to the usual dictionary (dict) container, but the only difference is that a defaultdict will have a default value if that key has not been set yet. If you didn’t use a defaultdict you’d have to check to see if that key exists, and if it doesn’t, set it to what you want.

For Example

from collections import defaultdictd = defaultdict(list)d['python'].append("awesome")d['something-else'].append("not relevant")d['python'].append("language")for i in d.items():    print i

This prints:

('python', ['awesome', 'language'])('something-else', ['not relevant'])

In this challenge, you will be given 2 integers, n and m. There are  words, which might repeat, in word group A.

There are m words belonging to word group B. For each m words, check whether the word has appeared in group  or not. Print the indices of each occurrence of m in group A. If it does not appear, print -1.

Example

Group A contains ‘a’, ‘b’, ‘a’ Group B contains ‘a’, ‘c’

For the first word in group B, ‘a’, it appears at positions 1 and 3 in group A. The second word, ‘c’, does not appear in group A, so print -1.

Expected output:

1 3-1

Input Format

The first line contains integers, n and m separated by a space.

The next n lines contains the words belonging to group A.

The next m lines contains the words belonging to group B.

Constraints

1 ≤ n ≤ 10000

1 ≤ m ≤ 100

1 ≤ lenght of each word in the input ≤100

Output Format

Output m lines.

The i^th line should contain the 1-indexed positions of the occurrences of the i^th word separated by spaces.

Sample Input

STDIN   Function-----   --------5 2     group A size n = 5, group B size m = 2a       group A contains 'a', 'a', 'b', 'a', 'b'ababa       group B contains 'a', 'b'b

Sample Output

1 2 43 5

Explanation

‘a’ appeared 3 times in positions 1, 2 and 4.
‘b’ appeared 2 times in positions 3 and 5.
In the sample problem, if ‘c’ also appeared in word group B, you would print -1.

Solution – HackerRank DefaultDict Tutorial Solution In Python

from collections import defaultdictd = defaultdict(list)n, m = list(map(int, input().split()))for i in range(1, n+1):    d[input()].append(i)for _ in range(m):    k = input()    if k in d:        print(*d[k])    else:        print(-1)