705. Design HashSet (Easy)
https://leetcode.com/problems/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.
Solutions
class MyHashSet {
private List<Integer> list = null;
public MyHashSet() {
list = new ArrayList<>();
}
public void add(int key) {
if (contains(key)) {
return;
}
list.add(key);
}
public void remove(Object key) {
list.remove(key);
}
public boolean contains(int key) {
return list.contains(key);
}
}