# 706.Design Hashmap

**706.Design Hashmap**

难度:Easy

> 不使用任何内建的哈希表库设计一个哈希映射

具体地说，你的设计应该包含以下的功能

```
put(key, value)：向哈希映射中插入(键,值)的数值对。如果键对应的值已经存在，更新这个值。
get(key)：返回给定的键所对应的值，如果映射中不包含这个键，返回-1。
remove(key)：如果映射中存在这个键，删除这个数值对。
```

```
示例：

MyHashMap hashMap = new MyHashMap();
hashMap.put(1, 1);          
hashMap.put(2, 2);         
hashMap.get(1);            // 返回 1
hashMap.get(3);            // 返回 -1 (未找到)
hashMap.put(2, 1);         // 更新已有的值
hashMap.get(2);            // 返回 1 
hashMap.remove(2);         // 删除键为2的数据
hashMap.get(2);            // 返回 -1 (未找到) 

注意：

所有的值都在 [1, 1000000]的范围内。
操作的总数目在[1, 10000]范围内。
不要使用内建的哈希库。
```

可以直接使用数组映射完成:

```
class MyHashMap {
public:
    /** Initialize your data structure here. */
    MyHashMap() {
        hmap=vector<int>(1000001,-1);
    }
    
    /** value will always be non-negative. */
    void put(int key, int value) {
        hmap[key]=value;
    }
    
    /** Returns the value to which the specified key is mapped, or -1 if this map contains no mapping for the key */
    int get(int key) {
        return hmap[key];
    }
    
    /** Removes the mapping of the specified value key if this map contains a mapping for the key */
    void remove(int key) {
        hmap[key]=-1;
        
    }
private:
    vector<int> hmap;
};

/**
 * 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);
 */
```


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