unozerocode / exercises

Various algorithm exercises and a list of books
Mozilla Public License 2.0
0 stars 1 forks source link

Find non-duplicate number #9

Closed unozerocode closed 4 years ago

unozerocode commented 5 years ago

Hi, here's your problem today. This problem was recently asked by Facebook:

Given a list of numbers, where every number shows up twice except for one number, find that one number.

Example: Input: [4, 3, 2, 4, 1, 3, 2] Output: 1 Here's the function signature:

def singleNumber(nums):
# Fill this in.

print singleNumber([4, 3, 2, 4, 1, 3, 2])
# 1

Challenge: Find a way to do this using O(1) memory.