Feat/380 insert delete getrandom.go

go/0380-insert-delete-getrandom.go

@@ -0,0 +1,43 @@
+import "math/rand"
+
+type RandomizedSet struct {
+	hash   map[int]int
+	array  []int
+	length int
+}
+
+func Constructor() RandomizedSet {
+	return RandomizedSet{
+		hash:   make(map[int]int),
+		array:  []int{},
+		length: 0,
+	}
+}
+
+func (this *RandomizedSet) Insert(val int) bool {
+	if _, ok := this.hash[val]; ok {
+		return false
+	}
+	this.array = append(this.array, val)
+	this.hash[val] = len(this.array) - 1
+	this.length++
+	return true
+}
+
+func (this *RandomizedSet) Remove(val int) bool {
+	idx, ok := this.hash[val]
+	if !ok {
+		return false
+	}
+	last := this.array[this.length-1]
+	this.array[idx] = last
+	this.hash[last] = idx
+	this.array = this.array[:len(this.array)-1]
+	delete(this.hash, val)
+	this.length--
+	return true
+}
+
+func (this *RandomizedSet) GetRandom() int {
+	return this.array[rand.Intn(this.length)]
+}