#2997
Minimum Number of Operations to Make Array XOR Equal to K
MediumArrayBit ManipulationBit ManipulationXOR properties
Approaches
Brute ForceOptimal
Complexity Comparison
| Brute Force | Optimal Solution★ | |
|---|---|---|
| Time | O(n²) | O(n) |
| Space | O(1) | O(1) |
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Intuition
Time O(n)Space O(1)
The optimal solution focuses on calculating the difference between the initial XOR and k. Each differing bit indicates a necessary flip. This approach is efficient because it directly counts the required flips without exploring all combinations.
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Algorithm
3 steps- 1Step 1: Calculate the initial XOR of all elements in the array.
- 2Step 2: Calculate the XOR difference between the initial XOR and k.
- 3Step 3: Count the number of differing bits in the XOR difference, which gives the minimum number of flips required.
solution.py9 lines
1# Full working Python code
2
3def min_operations_optimal(nums, k):
4 initial_xor = 0
5 for num in nums:
6 initial_xor ^= num
7 xor_diff = initial_xor ^ k
8 return bin(xor_diff).count('1')
9ℹ
Complexity note: The complexity is O(n) because we only make a single pass through the array to calculate the initial XOR and then a constant time operation to count the differing bits.
- 1The XOR operation is reversible and can be used to determine the bits that need to be flipped.
- 2Each differing bit between the initial XOR and k directly corresponds to a necessary flip.
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