leetcode_4th_dailychallange

706. Design HashMap

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class MyHashMap{
        final ListNode[] nodes = new ListNode[10_000];

        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){
                ListNode prev = find(nodes[i], key);
                if(prev.next != null)
                    prev.next = prev.next.next;
            }
        }

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

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

        class ListNode{
            int key, val;
            ListNode next;

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