Two Sum Optimization | Dataford Interview Questions

Solve the two sum problem, then optimise your solution from O(n) space down to O(1) space.

Asked in the Technical round stage. The candidate first produced an O(n)-space solution; the interviewer then pushed for O(1) space and he could not get there. Reported follow-up: Can you make it O(1) space complexity?

Implement def two_sum(nums, target):. Return the two values whose sum equals target, or [] if no pair exists. You may reorder nums.

Constraints

2 <= len(nums) <= 10^4
nums contains integers
target is an integer
The function may reorder nums
Return [] when no valid pair exists
Auxiliary space must remain O(1)

Function Signature

def two_sum(nums, target):

Your question is Two Sum Optimization. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem

Solve the two sum problem, then optimise your solution from O(n) space down to O(1) space.

Implement def two_sum(nums, target):. Return the two values whose sum equals target, or [] if no pair exists. You may reorder nums.

Constraints

2 <= len(nums) <= 10^4
nums contains integers
target is an integer
The function may reorder nums
Return [] when no valid pair exists
Auxiliary space must remain O(1)

Function Signature

def two_sum(nums, target):

Your question is Two Sum Optimization. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.