Design HashMap | LeetCode 706 | C++, Java, Python

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Design HashMap | Leetcode 706
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[sandeepraja]

Below is what I did!

class MyHashMap {

class Node {
int key;
int value;
Node next;
Node(int key, int value) {
this.key = key;
this.value = value;
}
}

Node[] bucket;
int maxSize;

public MyHashMap() {
maxSize = 16;
bucket = new Node[maxSize];
}

private int hashCode(int a) {
return a % maxSize;
}

private boolean equals(Node n, int key) {
if(n.key == key) return true;
return false;
}

public void put(int key, int value) {

int getHash = hashCode(key);
Node head = bucket[getHash];

//check if already present
Node curr = head;
while(curr != null) {
if(equals(curr, key)) {
curr.value = value;
return;
}
curr = curr.next;
}
//if not present
Node temp = new Node(key, value);
temp.next = head;
head = temp;
bucket[getHash] = head;
}

public int get(int key) {

int getHash = hashCode(key);
Node head = bucket[getHash];
if(head == null) return -1;

Node curr = head;
while(curr != null) {
if(equals(curr, key)) {
return curr.value;
}
curr = curr.next;
}
return -1;
}

public void remove(int key) {
int getHash = hashCode(key);
Node head = bucket[getHash];
if(head == null) return;

if(equals(head, key))
bucket[getHash] = head.next;
else{
Node curr = head;
while(curr != null) {
if(curr.next != null && equals(curr.next, key)) {
curr.next = curr.next.next;
}
curr = curr.next;
}
bucket[getHash] = head;
}
}
}

[AB-frqn]

Sir, I can't understand how you initialized the vector in the constructor. I am doing same but instead to that I am using memset in the constructor and it's not working.Please explain, Thank you.

[sihanyang]

Thanks for the solution. But when I use this java answer. The compiler will have an error that says: Index 250005 out of bounds for length 100001; Is this because the lc change the statement of the question? Thanks!

[praveenj]

this is good . but you are not using Hashing technique here . Like Linear probing and chaining . using hash fucntion, we can map key value pairs using array of buckets of some size. Using this approach time complexity depends upon the load factor.

Thank you.

[abhisheksuryavanshi]

Could you please tell us the other method as well

[dataman]

This solution cannot be used in interviews....
We were expecting space optimized version.