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DefaultDict Tutorial

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  • 22cs0324
     + 0 comments

    from collections import defaultdict import sys input = sys.stdin.read data = input().splitlines()

    n, m = map(int, data[0].split()) group_a = data[1:n+1]

    group_b = data[n+1:]

    word_positions = defaultdict(list)

    for idx, word in enumerate(group_a, 1): word_positions[word].append(str(idx))

    for word in group_b: if word in word_positions: print(" ".join(word_positions[word])) else: print("-1")

  • Solspin
     + 0 comments
    from collections import defaultdict

d = defaultdict(str)
n,m = map(int,input().split())
for i in range(n): d[input()]+=f'{i+1} '
for i in range(m): print(d.get(input(),-1))

    .get() allows a simple way to print the value or -1 and avoids creating new values in defaultdict

  • greivin_lopez
     + 0 comments
    from collections import defaultdict

def main():
    counts = input().split()
    n = int(counts[0])
    m = int(counts[1])
    group_a = defaultdict(list)
    for i in range(n):
        element = input()
        group_a[element].append(i+1)
    for _ in range(m):
        element = input()
        if group_a[element] == []:
            print(-1)
        else:
            print(" ".join(str(x) for x in group_a[element]))

if __name__ == "__main__":
    main()

  • nicolemoye7
     + 0 comments

    Thanks, HackerRank, for making Python collections feel less intimidating. Looking forward to applying this in more complex problems! Cricbet99 club login

  • pithambar20
     + 0 comments
    from collections import defaultdict

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

d = defaultdict(list)

for _ in range(n):
    d['A'].append(input().strip())

for _ in range(m):
    d['B'].append(input().strip())

for item in d['B']:
    positions = [i+1 for i, val in enumerate(d['A']) if val.strip().lower() == item.lower()]
    if positions:
        print(*positions)
    else:
        print(-1)
'