706. Design HashMap (Easy)

https://leetcode.com/problems/design-hashmap/

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.

Hints

Solutions

https://github.com/varunu28/LeetCode-Java-Solutions/blob/master/Easy/Design%20HashMap.java

class MyHashMap {

    /** Initialize your data structure here. */
    int[] arr;
    public MyHashMap() {
        arr = new int[1000001];
        Arrays.fill(arr, -1);
    }

    /** value will always be non-negative. */
    public void put(int key, int value) {
        arr[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) {
        return arr[key];
    }

    /** Removes the mapping of the specified value key if this map contains a mapping for the key */
    public void remove(int key) {
        arr[key] = -1;
    }
}

/**
 * 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);
 */
Copyright © iovi.com 2017 all right reserved,powered by GitbookLast Modification: 2019-04-09 12:38:15

results matching ""

    No results matching ""