Write a function to generate all combinations of k elements from a given list of n elements.
HardProblem Statement
Write a function to generate all combinations of k elements from a given list of n elements.
Sample Input
[1, 2, 3, 4], 2
Sample Output
[(1, 2), (1, 3), (1, 4), (2, 3), (2, 4), (3, 4)]
Limits
Time: 2s · Memory: 256 MB