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Challenges

59 challenges — solve one in the browser and get graded on correctness and speed.

All cgorust

backtracking 6

Fallback Chain Selector medium

backtracking, pruning, networking

backtrackingnetworkingscheduling
go
Feature Flag Compatibility Solver medium

backtracking, constraint satisfaction, configuration

backtrackingconfiguration
go
Glob / Path Pattern Matcher medium

backtracking, string matching, recursion

backtrackingstrings
go
Migration Step Ordering with Optional Steps medium

backtracking, topological sort, configuration

backtrackinggraphsconfiguration
go
Permission / Role Assignment Solver medium

backtracking, constraint satisfaction, RBAC

backtrackinggraphsconfiguration
go
CIDR Subnet Allocator medium

backtracking, constraint satisfaction, networking

backtrackingnetworkingconfiguration
go

caching 5

Consistent Hashing medium

consistent hashing, virtual nodes, hash ring

cachingdistributed
go
LFU Cache hard

cache eviction, O(1) LFU, frequency buckets

cachingdata-structures
go
SIEVE Cache medium

cache eviction, doubly-linked list, SIEVE

cachingdata-structures
go
Stale-While-Revalidate Cache medium

caching, background refresh, request coalescing, concurrency

cachingconcurrency
go
TTL Cache medium

sync.RWMutex, time.AfterFunc, Generics, Comparable

cachingconcurrency
go

concurrency 7

Batcher medium

generics, time.Timer, channels, graceful shutdown

concurrencybatching
go
Generic Concurrent Runner easy

Generics, Goroutines, Channels, Context, Benchmarks

concurrencygenerics
go
Channel Pipeline medium

Channels, Goroutines, Generics, Context

concurrencychannels
go
Pub/Sub Broker medium

sync.RWMutex, Channels, Goroutines, Generics

concurrencypub-sub
go
Token-Bucket Rate Limiter medium

Channels, time.Ticker, Context

concurrencyrate-limiting
go
Retry with Exponential Backoff easy

Generics, Context, time.Timer, Exponential backoff

concurrencyresilience
go
Singleflight medium

sync.Mutex, sync.WaitGroup, Goroutines, Generics

concurrencydeduplication
go

crypto 2

AES-256-GCM Authenticated Encryption medium

symmetric encryption, AEAD, AES-GCM, nonces

cryptoencryption
go
Asymmetric JWT (RS256) + Key Rotation hard

RSA, RS256, JWT, JWKS, key rotation, asymmetric crypto

cryptoauthjwt
go

data-structures 5

B-Tree (ordered map) hard

B-tree, balanced search tree, ordered map, range scan

data-structurestrees
go
Interval / Range Index medium

intervals, binary search, ordered index, overlap queries

data-structuressearch
go
LRU Cache medium

doubly-linked list, hash map, generics, O(1) eviction

data-structurescaching
go
LSM Memtable + Merge medium

LSM-tree, memtable, tombstones, k-way merge, compaction

data-structuresstorage
go
Skip List medium

skip list, probabilistic ordered map, range scan

data-structurestrees
go

graphs 8

Outage Blast Radius medium

graphs, BFS, resilience

graphsresilience
go
Bounded Concurrent Crawler hard

graphs, BFS, concurrency, worker pool, visited dedup

graphsconcurrency
go
CNAME / Redirect Chain Resolver easy

graphs, chain walk, loop detection

graphsnetworking
go
Config Include Resolver medium

graphs, DFS, cycle detection, gateway configuration

graphsconfiguration
go
DAG Pipeline Scheduler hard

graphs, topological sort, concurrency, worker pool

graphsconcurrency
go
Service Dependency Resolver medium

graphs, topological sort, orchestration

graphsorchestration
go
RBAC Role Inheritance medium

graphs, DFS, cycle detection, authorization

graphsauthorization
go
Trace Tree & Critical Path medium

graphs, DFS, observability, trace analysis

graphsobservability
go

leetcode 5

Binary Search easy

search, algorithms

leetcodesearchalgorithms
go
Valid Anagram easy

strings, hash map

leetcodestringshash-map
go
Maximum Subarray medium

dynamic programming, array

leetcodedynamic-programmingarray
go
Two Sum easy

Array, Hash Map

leetcodearrayhash-map
go
Valid Parentheses easy

stack, strings

leetcodestackstrings
go

networking 18

Circuit Breaker medium

State machine, sync.Mutex, time, error handling

networkingresilience
go
Connection Pool medium

Channels, Generics, io.Closer, Context

networkingconcurrency
go
Graceful HTTP Shutdown easy

http.Server, context, connection draining, high availability

networkinghttp
go
gRPC Unary Interceptor Chain medium

gRPC, interceptors, middleware composition

networkinggrpc
go
HTTP Retry Client medium

http.RoundTripper, http.Client, context, backoff

networkinghttpresilience
go
JWT Auth Middleware medium

HMAC-SHA256, base64url, JSON, HTTP middleware, context

networkingauthjwt
go
Line-Protocol TCP Server hard

TCP, line protocol, concurrency, graceful drain

networkingtcp
go
Message Framing (length-prefix) medium

stream framing, length-prefix protocol, partial reads

networkingprotocols
go
Observability Middleware (RED metrics) medium

HTTP middleware, ResponseWriter wrapping, atomics, RED metrics

networkingobservability
go
HTTP Middleware Chain easy

http.Handler, http.HandlerFunc, function composition

networkinghttp
go
mTLS Handshake medium

crypto/tls, crypto/x509, certificate chains, mutual TLS

networkingcryptotls
go
Redis Fixed-Window Rate Limiter medium

Redis (INCR/EXPIRE), distributed rate limiting, go-redis

networkingrate-limitingredis
go
Request Queue medium

bounded channels, backpressure, graceful shutdown, generics

networkingbackpressure
go
RESP mini-server (Redis) medium

wire-protocol parsing, RESP, in-memory store

networkingprotocols
go
Reverse Proxy / Load Balancer medium

httputil.ReverseProxy, round-robin, health checks, atomics

networkingload-balancing
go
SSE Streaming Proxy + Token Metering hard

Server-Sent Events, http.Flusher, streaming, context cancellation, token metering

networkingstreamingsse
go
TCP Echo Server easy

net.Listen, goroutines, io.Copy, context, SetDeadline

networkingtcp
go
WebSocket Echo (RFC 6455) hard

HTTP Upgrade, frame format, masking, ping/pong

networkingwebsocket
go

profiling 2

Data-Race Hunt (Go Memory Model) medium

Go memory model, -race detector, sync.Mutex, sync/atomic

profilingconcurrency
go go-only by design ⓘ
pprof Bottleneck Hunt medium

go tool pprof, CPU profiling, memory profiling, Go runtime/GC

profilingperformance
go go-only by design ⓘ

scheduling 1

Job Placement Scheduler medium

backtracking, constraint satisfaction, scheduling

schedulingbacktracking
go