package LeetCode_706
/**
* 706. Design HashMap
* https://leetcode.com/problems/design-hashmap/description/
*
* 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.
* */
class MyHashMap() {
/** Initialize your data structure here. */
val size = 1000
var keys: Array<ArrayList<Pair<Int, Int>>>? = null
init {
keys = Array(size, { ArrayList<Pair<Int, Int>>() })
}
/** value will always be non-negative. */
fun put(key: Int, value: Int) {
var list = keys!![getHash(key)]
if (list == null) {
list = ArrayList()
keys!![getHash(key)] = list
}
//if key exist, replace value
for (item in list) {
if (item.first == key) {
list.remove(item)
val itemClone = item.copy(first = key, second = value)
list.add(itemClone)
return
}
}
list.add(Pair(key, value))
}
/** Returns the value to which the specified key is mapped, or -1 if this map contains no mapping for the key */
fun get(key: Int): Int {
val list = keys!![getHash(key)]
if (list == null) {
return -1
}
for (item in list) {
if (item.first == key) {
return item.second
}
}
return -1
}
/** Removes the mapping of the specified value key if this map contains a mapping for the key */
fun remove(key: Int) {
val list = keys!![getHash(key)]
if (list != null) {
for (item in list) {
if (item.first == key) {
list.remove(item)
return
}
}
}
}
private fun getHash(key: Int): Int {
return key % size
}
}
/**
* Your MyHashMap object will be instantiated and called as such:
* var obj = MyHashMap()
* obj.put(key,value)
* var param_2 = obj.get(key)
* obj.remove(key)
*/
