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### by Sumit Chourasia | Sep 29, 2020 | Category :coding | Tags : algorithmडेटा-संरचनाआसानhash-tableleetcode

#### Design HashMap - Hash Table - Easy - LeetCode - मिनी टीवी

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.put(2, 1);          // update the existing value
hashMap.get(2);            // returns 1
hashMap.remove(2);          // remove the mapping for 2

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)

Contributed By: Sumit Chourasia
Contributed By: Sumit Chourasia
Contributed By: Sumit Chourasia
Contributed By: Sumit Chourasia