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  1. Prepare
  2. Python
  3. Collections
  4. DefaultDict Tutorial
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DefaultDict Tutorial

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1084 Discussions

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  • coding_a5i
     + 0 comments

    from collections import defaultdict n,m,dd = map(int,input().split()),defaultdict(list)

    for i in range(n): dd[input()].append(i+1)

    for _ in range(m): print(' '.join(map(str,dd.get(input(),[-1]))))

  • sean_wang_sq
     + 0 comments

    The statement of this problem is so confusing... spent most of my time figure out where does the m and n come from.. 

    from collections import defaultdict

n, m = map(int, input().split())

d = defaultdict(list)
for i in range(n):
    word = input()
    d[word].append(i + 1)

for j in range(m):
    word = input()
    if len(d[word]) > 0:
        print(' '.join([str(s) for s in d[word]]))
    else:
        print(-1)

  • vmmulik
     + 0 comments

    Here is my code

    from collections import defaultdict

n, m = input().split()

result = defaultdict(list)

for index, _ in enumerate(range(int(n)),1):
    val = input()
    # result[val] = result[val].append(index) if val in result else [index]
    result[val].append(index)
    
for _ in range(int(m)):
    b_val = input()
    if b_val in result:
        print(*result[b_val])
    else:
        print(-1)

  • nits86
     + 1 comment

    What's wrong with below code, why all the test cases are not passing.

    from collections import defaultdict

    d=defaultdict(list)

    A = ['a','b','a','b']

    B= ['c']

    for i in B:

    if i in A:

    for index,j in enumerate(A):

        if i==j:

            d[i].append(index+1)

else:

    d[i].append(int(-1))

    for values in d.values():

    print(*values)

  • k252438
     + 1 comment
    # Enter your code here. Read input from STDIN. Print output to STDOUT
len_a, len_b = input().split()
a, b = list(), list()
for i in range(int(len_a)+int(len_b)):
    if i < int(len_a):
        a.append(input())
    else:
        b = input()
        out = ""
        for j in range(len(a)):
            if b == a[j]:
                out += str(j+1) + " "
        if b not in a:
            out = "-1"
        print(out)