Design a HashMap without using any built-in hash table libraries.
To be specific, your design should include these functions:
put(key, value) : Insert a (key, value) pair into the HashMap. If the value already exists in the HashMap, update the value. get(key): Returns the value to which the specified key is mapped, or -1 if this map contains no mapping for the key. remove(key) : Remove the mapping for the value key if this map contains the mapping for the key.
Example:
MyHashMap hashMap = new MyHashMap(); hashMap.put(1, 1); hashMap.put(2, 2); hashMap.get(1); // returns 1 hashMap.get(3); // returns -1 (not found) hashMap.put(2, 1); // update the existing value hashMap.get(2); // returns 1 hashMap.remove(2); // remove the mapping for 2 hashMap.get(2); // returns -1 (not found)
Note:
All keys and 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 HashMap library.
public class MyHashMap {
/** Initialize your data structure here. */
int[] hasharray;
public MyHashMap() {
hasharray = new int[1000000];
Array.Fill(hasharray, Int32.MinValue);
}
/** value will always be non-negative. */
public void Put(int key, int value) {
hasharray[key] = value;
}
/** Returns the value to which the specified key is mapped, or -1 if this map contains no mapping for the key */
public int Get(int key) {
if (hasharray[key]!=Int32.MinValue)
return hasharray[key];
return -1;
}
/** Removes the mapping of the specified value key if this map contains a mapping for the key */
public void Remove(int key) {
hasharray[key] = Int32.MinValue;
}
}
/**
* Your MyHashMap object will be instantiated and called as such:
* MyHashMap obj = new MyHashMap();
* obj.Put(key,value);
* int param_2 = obj.Get(key);
* obj.Remove(key);
*/Time Complexity: O(1)
Space Complexity: O(n)
