How should I practice Two Sum?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Google phone screen and onsite interview problems in FastPrep.

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FastPrep tags this as a Google phone screen and onsite interview coding practice problem when the problem catalog has that company and stage context.

Two Sum

Google● EasyINTERNFULLTIMEPHONE SCREENONSITE INTERVIEW

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Problem statement

Given an integer array nums and an integer target, return the two distinct indices whose values add up to target.

Exactly one valid pair exists. Return the smaller index first.

Function

twoSum(nums: int[], target: int) → int[]

Examples

Example 1

nums = [2,7,11,15]target = 9return = [0,1]

nums[0] + nums[1] = 2 + 7 = 9.

Example 2

nums = [3,2,4]target = 6return = [1,2]

nums[1] + nums[2] = 2 + 4 = 6.

Example 3

nums = [3,3]target = 6return = [0,1]

The two equal values occur at distinct indices.

Constraints

2 <= nums.length <= 10000.
-1000000000 <= nums[i], target <= 1000000000.
Exactly one valid answer exists.

Source note: Author-written prompt excerpt retained for source fidelity.