706. 设计哈希映射
作者:互联网
706. 设计哈希映射
不使用任何内建的哈希表库设计一个哈希映射(HashMap)
。
实现MyHashMap
类:
MyHashMap()
用空映射初始化对象
void put(int key, int value)
向 HashMap 插入一个键值对 (key, value) 。如果 key 已经存在于映射中,则更新其对应的值 value 。
int get(int key)
返回特定的 key 所映射的 value ;如果映射中不包含 key 的映射,返回 -1 。
void remove(key)
如果映射中存在 key 的映射,则移除 key 和它所对应的 value 。
class MyHashMap {
private class Pair {
private int key;
private int value;
public Pair(int key, int value) {
this.key = key;
this.value = value;
}
public int getKey() {
return key;
}
public int getValue() {
return value;
}
public void setValue(int value) {
this.value = value;
}
}
private static final int BASE = 769;
private LinkedList[] data;
/** Initialize your data structure here. */
public MyHashMap() {
data = new LinkedList[BASE];
for (int i = 0; i < BASE; ++i) {
data[i] = new LinkedList<Pair>();
}
}
/** value will always be non-negative. */
public void put(int key, int value) {
int h = hash(key);
Iterator<Pair> iterator = data[h].iterator();
while (iterator.hasNext()) {
Pair pair = iterator.next();
if (pair.getKey() == key) {
pair.setValue(value);
return;
}
}
data[h].offerLast(new Pair(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) {
int h = hash(key);
Iterator<Pair> iterator = data[h].iterator();
while (iterator.hasNext()) {
Pair pair = iterator.next();
if (pair.getKey() == key) {
return pair.value;
}
}
return -1;
}
/** Removes the mapping of the specified value key if this map contains a mapping for the key */
public void remove(int key) {
int h = hash(key);
Iterator<Pair> iterator = data[h].iterator();
while (iterator.hasNext()) {
Pair pair = iterator.next();
if (pair.key == key) {
data[h].remove(pair);
return;
}
}
}
private static int hash(int key) {
return key % BASE;
}
}
/**
* 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);
*/
标签:哈希,映射,int,706,value,key,pair,iterator,data 来源: https://blog.csdn.net/weixin_41884690/article/details/114794627