_706.java

package com.fishercoder.solutions;

public class _706 {
    public static class Solution1 {
        /**
         * credit: https://leetcode.com/problems/design-hashmap/discuss/152746/Java-Solution
         */
        class MyHashMap {

            final ListNode[] nodes = new ListNode[10000];

            public void put(int key, int value) {
                int i = idx(key);
                if (nodes[i] == null) {
                    nodes[i] = new ListNode(-1, -1);
                }
                ListNode prev = find(nodes[i], key);
                if (prev.next == null) {
                    prev.next = new ListNode(key, value);
                } else {
                    prev.next.val = value;
                }
            }

            public int get(int key) {
                int i = idx(key);
                if (nodes[i] == null) {
                    return -1;
                }
                ListNode node = find(nodes[i], key);
                return node.next == null ? -1 : node.next.val;
            }

            public void remove(int key) {
                int i = idx(key);
                if (nodes[i] == null) {
                    return;
                }
                ListNode prev = find(nodes[i], key);
                if (prev.next == null) {
                    return;
                }
                prev.next = prev.next.next;
            }

            int idx(int key) {
                return Integer.hashCode(key) % nodes.length;
            }

            ListNode find(ListNode bucket, int key) {
                ListNode node = bucket;
                ListNode prev = null;
                while (node != null && node.key != key) {
                    prev = node;
                    node = node.next;
                }
                return prev;
            }

            class ListNode {
                int key;
                int val;
                ListNode next;

                ListNode(int key, int val) {
                    this.key = key;
                    this.val = val;
                }
            }
        }

/**
 * 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);
 */
    }
}