Code RoomFind duplicate number
MediumPrep Room Coding #1141

Find duplicate number

CodingAlgorithms & data structuresMid–Senior~24 min

Given an array nums of n+1 integers where every value is in the range [1, n], exactly one value is duplicated (possibly multiple times). Return that duplicated value without modifying the array and using only O(1) extra space. Array length up to 1e5.

Implement
find_duplicate(nums: list[int]) → int
Examples
in[[1,3,4,2,2]]out2
What a strong answer looks like

State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.

0:00 of about 24 min
InputExpectedGot
[[1,3,4,2,2]]2not run yetsample