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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.
程序如下所示：
class MyHashSet {
List<List<Integer>> table = new ArrayList<>(127);
/** Initialize your data structure here. */
public MyHashSet() {
for (int i = 0; i < 127; ++ i){
table.add(new LinkedList<Integer>());
}
}
public void add(int key) {
List<Integer> tmp = table.get(key%127);
int len = tmp.size();
for (int i = 0; i < len; ++ i){
if (tmp.get(i) == key){
return;
}
}
tmp.add(key);
}
public void remove(int key) {
List<Integer> tmp = table.get(key%127);
int len = tmp.size();
for (int i = 0; i < len; ++ i){
if (tmp.get(i) == key){
tmp.remove(i);
return;
}
}
}
/** Returns true if this set contains the specified element */
public boolean contains(int key) {
List<Integer> tmp = table.get(key%127);
int len = tmp.size();
for (int i = 0; i < len; ++ i){
if (tmp.get(i) == key){
return true;
}
}
return false;
}
}
/**
* 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);
*/