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  4. DefaultDict Tutorial
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DefaultDict Tutorial

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1055 Discussions

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  • deepakm1402
     + 0 comments

    from collections import defaultdict d = defaultdict(list) list1=[]

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

    for i in range(0,n): d[input()].append(i+1)

    for i in range(0,m): list1=list1+[input()]

    for i in list1: if i in d: print(" ".join( map(str,d[i]) )) else: print(-1)

  • jackmaney
     + 0 comments

    I fail to see the utility of defaultdicts for this problem. List comprehensions provide, IMO, more readable code:

    n, m = [int(x.strip()) for x in input().split()]

a = [input().strip() for _ in range(n)]

b = [input().strip() for _ in range(m)]

for w in b:
    indices = [i+1 for i, x in enumerate(a) if x == w]
    if indices:
        print(*indices)
    else:
        print(-1)

  • sayeedahmad06061
     + 0 comments

    n,m=[int(i) for i in input().split()] l1=[] l2=[] i=0 while(i

  • AshleySherrod34
     + 0 comments

    The defaultdict in Python is a powerful tool that simplifies dictionary handling by automatically assigning a default value to keys that don’t yet exist. This feature saves time and reduces code complexity, especially when dealing with cases where keys might not be initialized. Bc game

  • wweave42
     + 0 comments
    from collections import defaultdict
d = defaultdict(list)
n, m = map(int, input().split())

### Optimized Version ###
# Precompute the positions of each value in group_A
positions_dict = defaultdict(list)
for i in range(n):
    value = input()
    positions_dict[value].append(i + 1)  # Store 1-based index positions

# Check and print the positions for each value in group_B
for _ in range(m):
    value = input()
    if value in positions_dict:
        print(*positions_dict[value])  # Print all positions found
    else:
        print(-1)  # Print -1 if no occurrence found

### Less Efficient Version ###
# for _ in range(n):
#     d['group_A'].append(input())
# for _ in range(m):
#     d['group_B'].append(input())
    
# for value in d['group_B']:
#     positions = [i + 1 for i, v in enumerate(d['group_A']) if v == value]  # Find all occurrences
#     if positions:
#         print(*positions)  # Print all positions found
#     else:
#         print(-1)  # Print -1 if no occurrence found