Challenge Library
Coding Challenges
5,893 curated questions across every arena — browse by topic, then jump into a live 3-minute battle to put them to the test.
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2,721 challenges matching your filters
- Multiple ChoiceIntermediate
gcc -g
cintermediate - Multiple ChoiceIntermediate
gcc -O2
cintermediate - Multiple ChoiceIntermediate
GDB breakpoint
cintermediate - Multiple ChoiceIntermediate
GDB backtrace
cintermediate - Multiple ChoiceIntermediate
Valgrind Purpose
cintermediate - Multiple ChoiceIntermediate
Sequence Points
cintermediate - Multiple ChoiceIntermediate
Signed Overflow
cintermediate - Multiple ChoiceIntermediate
Null Pointer Deref
cintermediate - Multiple ChoiceIntermediate
Double Free
cintermediate - Multiple ChoiceIntermediate
Use After Free
cintermediate - Multiple ChoiceIntermediate
Stack Overflow
cintermediate - Multiple ChoiceIntermediate
Signal Handler
cintermediate - Multiple ChoiceIntermediate
setjmp/longjmp
cintermediate - Code AnalysisIntermediate
Macro Expansion Trap
code-analysisClanguage - Code AnalysisIntermediate
Post-increment Loop
code-analysisClanguage - Code AnalysisIntermediate
Pointer Arithmetic
code-analysisClanguage - Code AnalysisIntermediate
String Literal Length
code-analysisClanguage - Code AnalysisIntermediate
Ternary Operator
code-analysisClanguage - Code AnalysisIntermediate
Deleting derived through base pointer
cppvirtualdestructorundefined-behavior - Code AnalysisIntermediate
Capture by reference outliving scope
cpplambdacapturedangling - Code AnalysisIntermediate
Dangling reference in std::async
cppasynclambdacapture - Code AnalysisIntermediate
Return local by value
cpprvoreturncode-analysis - Code AnalysisIntermediate
Lambda returning reference to by-value capture
cpplambdadanglingreferences - Code AnalysisIntermediate
Virtual call during destruction
cppvirtualdestructorcode-analysis - Code AnalysisIntermediate
unordered_map pointer survives rehash
cppstlunordered_mapiterator-invalidation - Code AnalysisIntermediate
Reference to vector element across growth
cppstlvectordangling - Code AnalysisIntermediate
Brace init narrowing error
cppaggregate-initnarrowingcode-analysis - Code AnalysisIntermediate
const member mutating through pointer
cppconst-correctnesspointersgotcha - Code AnalysisIntermediate
new[] / delete mismatch
cppundefined-behaviornew-deletecode-analysis - Code AnalysisIntermediate
Range-for over returning-by-value container
cpprange-forlifetimecode-analysis - Code AnalysisIntermediate
Two-mutex lock-order deadlock
cppthreadingdeadlockmutex - Code AnalysisIntermediate
volatile increment not atomic
cppatomicsvolatiledata-race - Code AnalysisIntermediate
Detached thread using this
cppthreadingdanglinglambda - Code AnalysisIntermediate
std::thread destructor terminate
cppthreadingstd-threadcode-analysis - Code AnalysisIntermediate
sizeof object with vptr
cppsizeofvtablecode-analysis - Code AnalysisIntermediate
constexpr used as array bound
cppconstexprarraycode-analysis - Code AnalysisIntermediate
vector uses copy when move may throw
cppexception-safetynoexceptvector - Code AnalysisIntermediate
Infinite loop optimized away
cppatomicsundefined-behavioroptimization - Code AnalysisIntermediate
Calling empty std::function
cppstd-functioncode-analysis - Code AnalysisIntermediate
No implicit void* conversion
cpptypingvoid-pointercode-analysis - Code AnalysisIntermediate
Iterator invalidation while erasing in a vector loop
iterator-invalidationvectorerase - Code AnalysisIntermediate
Dangling pointer to a local vector's data
dangling-pointervectorlifetime - Code AnalysisIntermediate
Attempting to copy a unique_ptr
unique-ptrmove-onlycompile-error - Code AnalysisIntermediate
Cross-thread visibility with a relaxed flag
memory-orderatomicsdata-race - Code AnalysisIntermediate
Self-deadlock from locking a non-recursive mutex twice
deadlockmutexconcurrency - Code AnalysisIntermediate
Missing std::forward loses value category
perfect-forwardingstd-forwardvalue-category - Code AnalysisIntermediate
atomic double CAS loop output
atomicsfloating-pointcode-analysis - Code AnalysisIntermediate
flat_map sort key output
flat_mapcontainerscode-analysis - Code AnalysisIntermediate
structured binding reference output
structured-bindingsrange-forcode-analysis - Code AnalysisIntermediate
pimpl unique_ptr inline dtor output
pimplunique_ptrincomplete-typecode-analysis - Code AnalysisIntermediate
to_chars buffer too small output
to_charsnumericcode-analysis - Code AnalysisIntermediate
Coroutine Frame Dangling Reference
coroutineslifetimedebugging - Code AnalysisIntermediate
Suspended Coroutine Parameter Lifetime
coroutinesframesparameters - Code AnalysisIntermediate
Barrier Completion Function Deadlock
barrierdeadlockphases - Code AnalysisIntermediate
Semaphore Release Overrun
semaphoreubcounters - Code AnalysisIntermediate
atomic_ref Misalignment
atomic_refalignmentlayout - Code AnalysisIntermediate
void_t detection idiom SFINAE
SFINAEvoid_tdetection-idiom - Code AnalysisIntermediate
MPMC queue index race root cause
MPMClock-freedata-race - Code AnalysisIntermediate
Dependent base member lookup
dependent-basetwo-phase-lookuptemplates - Code AnalysisIntermediate
Most vexing parse snippet
most-vexing-parsesyntaxdeclaration
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