首先我们看一下golang里面map的数据结构,map的核心数据结构是hmap,bmap是拉链式哈希表中的桶(bucket): // A header for a Go map.typehmapstruct{// Note: the format of the hmap is also encoded in cmd/compile/internal/gc/reflect.go.// Make sure this stays in sync with the compiler's definit...
countint// map中kv键值对的数量flagsuint8// 状态标识符,比如正在被写,buckets和oldbuckets正在被遍历或扩容Buint8// 2^B=len(buckets)noverflowuint16// 溢出桶的大概数量,当B小于16时是准确值,大于等于16时是大概的值hash0uint32// hash因子buckets unsafe.Pointer// 指针,指向一个[]bmap类型的数组,数组...
=0{throw("concurrent map iteration and map write")}t:=it.tbucket:=it.bucketb:=it.bptri:=it.icheckBucket:=it.checkBucketnext:ifb==nil{ifbucket==it.startBucket&&it.wrapped{// end of iterationit.key=nilit.elem=nilreturn}// ...bucket++ifbucket==bucketShift(it.B){bucket=0it.wrapped=...
//make(map[k]v, hint), hint即预分配大小//不传hint时,如用new创建个预设容量为0的map时,makemap只初始化hmap结构,不分配hash数组func makemap(t *maptype, hintint, h *hmap) *hmap {//省略部分代码//随机hash种子h.hash0 =fastrand()//2^h.B 为大于hint*6.5(扩容因子)的最小的2的幂B :=...
type Node struct {value int}type Graph struct {nodes []*Node // 节点集edges map[Node][]*Node // 邻接表表示的无向图lock sync.RWMutex // 保证线程安全} 操作实现 // 增加节点func (g *Graph) AddNode(n *Node) {g.lock.Lock()defer g.lock.Unlock()g.nodes = append(g.nodes, n)}//...
packagemazeimport("fmt")funcSetWay(myMap*[8][7]int,i int,j int)bool{//分析什么情况下就找到通路ifmyMap[6][5]==2{returntrue}else{//如果是可以探测的ifmyMap[i][j]==0{//假设是通的myMap[i][j]=2//依据下右上左进行探测ifSetWay(myMap,i+1,j){returntrue}elseifSetWay(myMap,i,...
When iterating over a map with a range loop, the iteration order is not specified and is not guaranteed to be the same from one iteration to the next. If you require a stable iteration order you must maintain a separate data structure that specifies that order.示例，playground，代码拷贝自...
g.edges = make(map[Node][]*Node) } g.edges[*u] = append(g.edges[*u], v) // 建立 u->v 的边 g.edges[*v] = append(g.edges[*v], u) // 由于是无向图,同时存在 v->u 的边 } // 输出图 func (g *Graph) String() { ...
package data_structure import ( "fmt" "learning/gooop/data_structure/hashmap" "strconv" "testing" "time" ) func Test_HashMap(t *testing.T) { fnAssertTrue := func(b bool, msg string) { if !b { t.Fatal(msg) } } fnEquals := func(a interface{}, b interface{}) bool { ...
正如这里和这里所描述的, Go语言原生的map类型并不支持并发读写。concurrent-map提供了一种高性能的解决方案:通过对内部map进行分片,降低锁粒度,从而达到最少的锁等待时间(锁冲突) 在Go 1.9之前,go语言标准库中并没有实现并发map。在Go 1.9中,引入了sync.Map。新的sync.Map与此concurrent-map有几个关键区别。标...