Go语言题解LeetCode705设计哈希集合

输入：
["MyHashSet", "add", "add", "contains", "contains", "add", "contains", "remove", "contains"]
[[], [1], [2], [1], [3], [2], [2], [2], [2]]
输出：
[null, null, null, true, false, null, true, null, false]
解释：
MyHashSet myHashSet = new MyHashSet();
myHashSet.add(1);      // set = [1]
myHashSet.add(2);      // set = [1, 2]
myHashSet.contains(1); // 返回 True
myHashSet.contains(3); // 返回 False ，（未找到）
myHashSet.add(2);      // set = [1, 2]
myHashSet.contains(2); // 返回 True
myHashSet.remove(2);   // set = [1]
myHashSet.contains(2); // 返回 False ，（已移除）

1,3,5,7,9

struct Listnode{
    int val;
    Listnode* next = nullptr;
    Listnode()=default;
    Listnode(int val){
        this->val = val;
    }
};
class MyHashSet {
public:
    /** Initialize your data structure here. */
    const int prime = 991;
    vector<Listnode*> nodes;
    MyHashSet(): nodes(prime, nullptr){
    }
    void add(int key) {
        if(nodes[key%prime] == nullptr){
            nodes[key%prime] = new Listnode(key);
        }else{
            Listnode* node = nodes[key%prime];
            while(node != nullptr){
                if(node->val == key)return;
                node = node->next;
            }
            node = new Listnode(key);
            node->next = nodes[key%prime];
            nodes[key%prime] = node;
        }
    }
    void remove(int key) {
        Listnode* prenode = nodes[key%prime];
        if(prenode != nullptr && prenode->val == key){
            if(prenode->next != nullptr){
                nodes[key%prime] = prenode->next;
                delete prenode;
            }else{
                delete prenode;
                nodes[key%prime] = nullptr;
            }
            return;
        }
        while(prenode != nullptr && prenode->next != nullptr){
            if(prenode->next->val == key){
                Listnode* temp = prenode->next;
                prenode->next = prenode->next->next;
                delete temp;
                return;
            }
            prenode = prenode->next;
        }
    }
    /** Returns true if this set contains the specif ied element */
    bool contains(int key) {
        Listnode* node = nodes[key%prime];
        while(node != nullptr){
            if(node->val == key)return true;
            node = node->next;
        }
        return false;
    }
};
/**
 * Your MyHashSet object will be instantiated and called as such:
 * MyHashSet* obj = new MyHashSet();
 * obj->add(key);
 * obj->remove(key);
 * bool param_3 = obj->contains(key);
 */