Design HashSet (E)
題目
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.
題意
實作一個只有add、contains、remove三個方法的HashSet，
思路
直接開一個boolean陣列進行hash，
代碼實作
Java
class MyHashSet {
private boolean[] hash;
/** Initialize your data structure here. */
public MyHashSet() {
hash = new boolean[1000001];
}
public void add(int key) {
hash[key] = true;
}
public void remove(int key) {
hash[key] = false;
}
/** Returns true if this set contains the specified element */
public boolean contains(int key) {
return hash[key];
}
}
/**
* Your MyHashSet object will be instantiated and called as such:
* MyHashSet obj = new MyHashSet();
* obj.add(key);
* obj.remove(key);
* boolean param_3 = obj.contains(key);
*/
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