Subsets Generation Using Bitmask in DSA Python - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to generate all subsets of a list using bitmask.

DSA Python

nums = [1, 2, 3]
subsets = []
n = len(nums)
for mask in range(1 << n):
    subset = []
    for i in range(n):
        if mask & (1 << [1]):
            subset.append(nums[i])
    subsets.append(subset)
print(subsets)

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Ai

Bsubset

Cn

Dmask

Attempts:

3 left

💡 Hint

Common Mistakes

Using mask instead of i in the bit shift.

Using n or subset instead of i for the bit position.

We use 'i' to check each bit position in the mask to decide if nums[i] is included in the subset.

2fill in blank

medium

Complete the code to calculate the total number of subsets using bitmask.

DSA Python

nums = [4, 5, 6, 7]
n = len(nums)
total_subsets = [1]
print(total_subsets)

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A2 * n

Bn * 2

C1 << n

Dn ** 2

Attempts:

3 left

💡 Hint

Common Mistakes

Using multiplication instead of bit shift.

Using n squared instead of 2 to the power n.

Total subsets of a set with n elements is 2^n, which is 1 shifted left by n bits.

3fill in blank

hard

Fix the error in the code to correctly generate subsets using bitmask.

DSA Python

nums = [8, 9]
n = len(nums)
subsets = []
for mask in range(1 << n):
    subset = []
    for i in range(n):
        if mask & (1 << i):
            subset.append(nums[[1]])
    subsets.append(subset)
print(subsets)

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Amask

Bi

Cn

Dsubset

Attempts:

3 left

💡 Hint

Common Mistakes

Appending nums[mask] instead of nums[i].

Using wrong variable in bit shift.

We must use 'i' to index nums, not 'mask', to get the correct element for the subset.

4fill in blank

hard

Fill both blanks to create a list of subsets with their sums using bitmask.

DSA Python

nums = [1, 2, 3]
n = len(nums)
subsets_with_sum = []
for mask in range(1 << n):
    subset = []
    for i in range(n):
        if mask & (1 << [1]):
            subset.append(nums[i])
    subsets_with_sum.append((subset, sum([2])))
print(subsets_with_sum)

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Ai

Bsubset

Cnums

Dmask

Attempts:

3 left

💡 Hint

Common Mistakes

Using nums instead of subset for sum.

Using mask or i instead of subset for sum.

Use 'i' to check bits and 'subset' to calculate the sum of elements included.

5fill in blank

hard

Fill all three blanks to create a dictionary mapping subsets (as tuples) to their sums using bitmask.

DSA Python

nums = [2, 4]
n = len(nums)
subset_sum_map = {}
for mask in range(1 << n):
    subset = []
    for i in range(n):
        if mask & (1 << [1]):
            subset.append(nums[i])
    subset_sum_map[tuple([2])] = [3]
print(subset_sum_map)

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Ai

Bsubset

Csum(subset)

Dnums

Attempts:

3 left

💡 Hint

Common Mistakes

Using nums instead of subset for key.

Using subset instead of sum(subset) for value.

Using wrong variable for bit check.

Use 'i' for bit check, 'subset' as key (converted to tuple), and sum(subset) as value.