380 adding

Author: aQua

Algorithms/0380.insert-delete-getrandom-o1/README.md

@@ -0,0 +1,41 @@
+# [380. Insert Delete GetRandom O(1)](https://leetcode.com/problems/insert-delete-getrandom-o1/)
+
+## 题目
+Design a data structure that supports all following operations in average O(1) time.
+
+1. `insert(val)`: Inserts an item val to the set if not already present.
+1. `remove(val)`: Removes an item val from the set if present.
+1. `getRandom`: Returns a random element from current set of elements. Each element must have the `same probability` of being returned.
+
+
+
+Example:
+```
+// Init an empty set.
+RandomizedSet randomSet = new RandomizedSet();
+
+// Inserts 1 to the set. Returns true as 1 was inserted successfully.
+randomSet.insert(1);
+
+// Returns false as 2 does not exist in the set.
+randomSet.remove(2);
+
+// Inserts 2 to the set, returns true. Set now contains [1,2].
+randomSet.insert(2);
+
+// getRandom should return either 1 or 2 randomly.
+randomSet.getRandom();
+
+// Removes 1 from the set, returns true. Set now contains [2].
+randomSet.remove(1);
+
+// 2 was already in the set, so return false.
+randomSet.insert(2);
+
+// Since 2 is the only number in the set, getRandom always return 2.
+randomSet.getRandom();
+```
+
+## 解题思路
+
+见程序注释

Algorithms/0380.insert-delete-getrandom-o1/insert-delete-getrandom-o1.go

@@ -0,0 +1,32 @@
+package Problem0380
+
+type RandomizedSet struct {
+}
+
+/** Initialize your data structure here. */
+func Constructor() RandomizedSet {
+
+}
+
+/** Inserts a value to the set. Returns true if the set did not already contain the specified element. */
+func (this *RandomizedSet) Insert(val int) bool {
+
+}
+
+/** Removes a value from the set. Returns true if the set contained the specified element. */
+func (this *RandomizedSet) Remove(val int) bool {
+
+}
+
+/** Get a random element from the set. */
+func (this *RandomizedSet) GetRandom() int {
+
+}
+
+/**
+ * Your RandomizedSet object will be instantiated and called as such:
+ * obj := Constructor();
+ * param_1 := obj.Insert(val);
+ * param_2 := obj.Remove(val);
+ * param_3 := obj.GetRandom();
+ */

Algorithms/0380.insert-delete-getrandom-o1/insert-delete-getrandom-o1_test.go

@@ -0,0 +1,12 @@
+package Problem0380
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_Problem0380(t *testing.T) {
+	ast := assert.New(t)
+
+}