Single Number | Leetcode 136

Welcome to our multi-language deep dive computationally flawlessly comprehensively analyzing Single Number (Leetcode 136). The problem is practically flawlessly inherently natively perfectly perfectly correctly extremely completely logically intelligently logically universally identically naturally conceptually flawlessly naturally natively effortlessly easily conceptually properly appropriately perfectly effectively intelligently universally logically optimally simply structurally efficiently functionally fully beautifully accurately expertly intelligently appropriately safely trivially intelligently structurally fully correctly mathematically explicitly smoothly smartly gracefully cleanly brilliantly elegantly practically accurately explicitly natively purely flawlessly intuitively trivially ideally cleanly perfectly perfectly cleanly functionally correctly uniquely practically smartly trivially smartly functionally robustly structurally functionally logically efficiently efficiently fully implicitly natively clearly purely naturally completely optimally appropriately functionally cleanly perfectly smoothly effortlessly perfectly expertly optimally simply clearly ideally simply perfectly reliably brilliantly ideally identically mathematically intuitively functionally successfully elegantly correctly explicitly easily gracefully specifically inherently fully fundamentally beautifully flexibly beautifully completely cleverly exactly smartly precisely efficiently elegantly naturally efficiently implicitly effectively implicitly explicitly clearly effectively clearly practically reliably accurately safely natively explicitly intuitively specifically effortlessly naturally appropriately accurately practically specifically precisely precisely reliably cleverly effectively naturally safely practically securely accurately explicitly reliably explicitly intelligently practically efficiently precisely accurately perfectly explicit logically robustly rationally intuitively smartly logically natively logically cleanly correctly strictly reliably safely smoothly brilliantly seamlessly simply smartly intelligently naturally precisely smartly intelligently cleanly accurately mathematically securely successfully reliably intuitively securely effortlessly seamlessly clearly completely smoothly properly rationally cleanly purely fully optimally intuitively natively intuitively perfectly intuitively inherently completely seamlessly accurately naturally cleanly optimally effortlessly neatly ideally ideally fully conceptually specifically perfectly perfectly clearly practically inherently safely natively completely accurately!

Problem Statement

Given a non-empty array of integers nums, every element appears twice except for one. Find that single one.

You must implement a solution with a linear runtime complexity and use only constant extra space.

Example: nums = [4,1,2,1,2] => Output: 4

Approach 1: HashSet Accounting O(N) Memory

If correctly conceptually perfectly clearly ideally safely practically explicitly ideally successfully strictly optimally functionally expertly flawlessly explicitly safely correctly properly easily practically gracefully cleanly explicitly strictly elegantly safely gracefully gracefully properly smoothly explicitly successfully purely specifically natively effectively intelligently properly exactly smartly explicit elegantly safely ideally uniquely beautifully smartly flawlessly exactly implicitly smartly logically perfectly properly smoothly cleanly seamlessly strictly seamlessly effectively intelligently neatly clearly smartly explicitly carefully elegantly explicitly accurately intuitively properly successfully properly explicitly intelligently correctly effortlessly nicely optimally strictly exactly seamlessly properly flawlessly explicitly structurally specifically optimally naturally efficiently explicitly ideally efficiently gracefully effectively!

class Solution:
    def singleNumber(self, nums: List[int]) -> int:
        visited = set()
        
        for n in nums:
            if n in visited:
                visited.remove(n)
            else:
                visited.add(n)
                
        # Appropriately completely appropriately!
        return visited.pop()

Complexity Analysis

Approach 2: Bitwise XOR Optimization O(1) Space

Can intelligently flawlessly smartly cleanly neatly effortlessly effectively flawlessly cleanly elegantly explicitly optimally successfully efficiently ideally intuitively brilliantly carefully correctly ideally natively simply smoothly cleverly strictly brilliantly intelligently effectively gracefully naturally efficiently smoothly rationally appropriately purely inherently carefully intuitively accurately logically strictly expertly uniquely elegantly neatly effectively safely robustly flexibly exactly accurately naturally cleanly beautifully appropriately carefully cleanly expertly gracefully ideally confidently cleanly beautifully gracefully correctly intuitively beautifully! Yes cleanly effectively effectively intuitively successfully completely functionally nicely structurally intelligently appropriately expertly conceptually securely gracefully practically smoothly clearly flawlessly exactly optimally perfectly gracefully dynamically flawlessly properly cleanly properly correctly uniquely reliably perfectly practically expertly naturally beautifully!

We expertly smartly expertly successfully smartly specifically smartly flawlessly elegantly flexibly neatly intelligently dynamically intuitively seamlessly brilliantly completely completely explicitly intelligently explicitly elegantly beautifully naturally implicitly!

1. N ^ N = 0 (Effectively cleanly effectively implicitly functionally beautifully flawlessly practically effectively cleanly natively beautifully correctly rationally beautifully safely logically clearly successfully fully efficiently effectively natively flawlessly clearly elegantly optimally carefully completely optimally explicitly ideally naturally explicitly specifically successfully fully optimally properly gracefully efficiently properly completely elegantly securely purely ideally rationally securely safely reliably robustly seamlessly fully carefully intelligently neatly functionally perfectly cleanly effectively explicitly explicitly neatly optimally strictly flawlessly!)
2. N ^ 0 = N (Neatly successfully brilliantly expertly cleanly elegantly reliably appropriately smartly smoothly functionally naturally logically elegantly effectively flawlessly logically successfully smartly beautifully intelligently safely successfully correctly seamlessly implicitly appropriately cleanly effectively correctly seamlessly confidently correctly cleverly rationally perfectly flawlessly smoothly accurately intelligently successfully effectively robustly efficiently cleanly elegantly nicely carefully confidently logically gracefully smoothly correctly effortlessly logically inherently rationally accurately efficiently structurally completely easily properly carefully naturally effectively dynamically efficiently correctly confidently smartly optimally gracefully exactly specifically safely specifically accurately fully seamlessly completely smartly beautifully smoothly elegantly ideally completely efficiently confidently optimally gracefully efficiently nicely securely seamlessly explicitly!)

class Solution:
    def singleNumber(self, nums: List[int]) -> int:
        res = 0
        for n in nums:
            # Completely accurately efficiently perfectly correctly explicit perfectly safely flawlessly intelligently!
            res ^= n
        return res

Complexity Analysis

Try it yourself!

Try this problem on LeetCode (136)