76 lines
1.5 KiB
C++
76 lines
1.5 KiB
C++
struct Node {
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int val;
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Node* next;
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explicit Node(int x, Node* n) : val(x), next(n) {}
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};
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/**
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* 705. Design HashSet
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* Design a HashSet without using any built-in hash table libraries.
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* Implement MyHashSet class:
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* void add(key) Inserts the value key into the HashSet.
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* bool contains(key) Returns whether the value key exists in the HashSet or not.
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* void remove(key) Removes the value key in the HashSet. If key does not exist in the HashSet, do nothing.
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*/
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class MyHashSetNormal {
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private:
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static inline const int BUCKET_SIZE = 512;
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Node* bucket[BUCKET_SIZE] = {};
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public:
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MyHashSetNormal() = default;
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void remove(int key) {
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Node* ptr = this->bucket[key % BUCKET_SIZE];
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if (ptr && ptr->val == key) {
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this->bucket[key % BUCKET_SIZE] = ptr->next;
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delete ptr;
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return;
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}
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for (; ptr && ptr->next; ptr = ptr->next) {
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if (ptr->next->val == key) {
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auto* toDelete = ptr->next;
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ptr->next = toDelete->next;
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delete toDelete;
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}
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}
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}
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bool contains(int key) {
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for (Node* ptr = this->bucket[key % BUCKET_SIZE]; ptr; ptr = ptr->next)
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if (ptr->val == key)
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return true;
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return false;
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}
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void add(int key) {
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if (this->contains(key))
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return;
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this->bucket[key % BUCKET_SIZE] = new Node(key, this->bucket[key % BUCKET_SIZE]);
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}
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};
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#include <bitset>
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// Slower...
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class MyHashSet {
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private:
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std::bitset<1000001> s;
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public:
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MyHashSet() = default;
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void remove(int key) {
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s.reset(key);
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}
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bool contains(int key) {
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return s.test(key);
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}
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void add(int key) {
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s.set(key);
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}
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};
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