leetcode tips

leetcode tips tips 在遍历时就max,min比较结果 返回的结果不计入空间花费 python str.isdigit() 正面不好解决时,从……

Golang Map的一些陷阱

通过结构体查询map 指针类型结构体 1type chunkType struct { 2 isUseOrderBy bool 3 isRoomBreak bool 4 a int 5} 6 7func pointerKey() { 8 m := make(map[*chunkType]int) 9 key :=……

Intresting Sql

字段升序,同时null值在非null值后面 如果只是根据字段升序 1select id,null_field from activity order by null_field; 2 3+----+------------+ 4| id……

检测图是否有环的各种方法

无向图 bfs 1from collections import deque 2 3def isCycle(n, d): 4 def bfs(start, visited): 5 q = deque([(start, None)]) 6 while len(q) > 0: 7 cur, parent = q.popleft() 8 if cur in visited: 9 return True 10 visited.add(cur) 11……

Kafka延迟队列

sequenceDiagram participant kafka participant delayService participant timewheel participant mysql kafka->>delayService: consume from delay topic(30min) delayService->>mysql: record delay msg(sendTime,delay,isSend) delayService-->>kafka: ack delayService-)timewheel: add to timewheel alt sendTime+delay>=now timewheel->>kafka: send to real topic timewheel->>mysql: update msg status else timewheel->>timewheel: next time cell end 根……

Grpc go服务端分析

grpc-go:v1.53.0 注册服务 1// helloworld_grpc.pb.go 2var Greeter_ServiceDesc = grpc.ServiceDesc{ 3 ServiceName: "helloworld.Greeter", 4 HandlerType: (*GreeterServer)(nil), 5 Methods: []grpc.MethodDesc{ 6 { 7 MethodName: "SayHello", 8 Handler: _Greeter_SayHello_Handler, 9 }, 10 }, 11 Streams: []grpc.StreamDesc{}, 12 Metadata: "helloworld/helloworld.proto", 13} 14 15type ServiceDesc……