705. Design HashSet

Design a HashSet without using any built-in hash table libraries.

To be specific, your design should include these functions:

• add(value): Insert a value into the HashSet.
• contains(value) : Return whether the value exists in the HashSet or not.
• remove(value): Remove a value in the HashSet. If the value does not exist in the HashSet, do nothing.

Example:

MyHashSet hashSet = new MyHashSet();
hashSet.add(1);
hashSet.add(2);
hashSet.contains(1);    // returns true
hashSet.contains(3);    // returns false (not found)
hashSet.add(2);
hashSet.contains(2);    // returns true
hashSet.remove(2);
hashSet.contains(2);    // returns false (already removed)

Note:

• All values will be in the range of [0, 1000000].
• The number of operations will be in the range of [1, 10000].
• Please do not use the built-in HashSet library.

# @lc code=start
using LeetCode

struct MyHashSet
    buckets::Int
    table::Vector{Vector{T}} where {T}
    MyHashSet() = new(1009, [[] for _ = 1:1009])
end

hash_705(hash_set::MyHashSet, key::Int) = mod1(key, hash_set.buckets)

function add_705!(hash_set::MyHashSet, key)
    hash_key = hash_705(hash_set, key)

    key ∈ hash_set.table[hash_key] && return

    push!(hash_set.table[hash_key], key)
    return
end

function remove_705!(hash_set::MyHashSet, key::Int)
    hash_key = hash_705(hash_set, key)

    key ∉ hash_set.table[hash_key] && return

    deleteat!(hash_set.table[hash_key], hash_set.table[hash_key] .== key)
end

function contains_705(hash_set::MyHashSet, key::Int)
    hash_key = hash_705(hash_set, key)

    return key ∈ hash_set.table[hash_key]
end
# @lc code=end

contains_705 (generic function with 1 method)

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