wincc oa使用笔记

题目：

题解：

type RandomizedSet struct {
    nums    []int
    indices map[int]int
}

func Constructor() RandomizedSet {
    return RandomizedSet{[]int{}, map[int]int{}}
}

func (rs *RandomizedSet) Insert(val int) bool {
    if _, ok := rs.indices[val]; ok {
        return false
    }
    rs.indices[val] = len(rs.nums)
    rs.nums = append(rs.nums, val)
    return true
}

func (rs *RandomizedSet) Remove(val int) bool {
    id, ok := rs.indices[val]
    if !ok {
        return false
    }
    last := len(rs.nums) - 1
    rs.nums[id] = rs.nums[last]
    rs.indices[rs.nums[id]] = id
    rs.nums = rs.nums[:last]
    delete(rs.indices, val)
    return true
}

func (rs *RandomizedSet) GetRandom() int {
    return rs.nums[rand.Intn(len(rs.nums))]
}