Leetcode 706. Design HashMap

Design a HashMap without using any built-in hash table libraries.

Implement the MyHashMap class:

• MyHashMap() initializes the object with an empty map.
• void put(int key, int value) inserts a (key, value) pair into the HashMap. If the key already exists in the map, update the corresponding value.
• int get(int key) returns the value to which the specified key is mapped, or -1 if this map contains no mapping for the key.
• void remove(key) removes the key and its corresponding value if the map contains the mapping for the key.

Example 1:

Input
["MyHashMap", "put", "put", "get", "get", "put", "get", "remove", "get"]
[[], [1, 1], [2, 2], [1], [3], [2, 1], [2], [2], [2]]
Output
[null, null, null, 1, -1, null, 1, null, -1]
Explanation
MyHashMap myHashMap = new MyHashMap();
myHashMap.put(1, 1); // The map is now [[1,1]]
myHashMap.put(2, 2); // The map is now [[1,1], [2,2]]
myHashMap.get(1);    // return 1, The map is now [[1,1], [2,2]]
myHashMap.get(3);    // return -1 (i.e., not found), The map is now [[1,1], [2,2]]
myHashMap.put(2, 1); // The map is now [[1,1], [2,1]] (i.e., update the existing value)
myHashMap.get(2);    // return 1, The map is now [[1,1], [2,1]]
myHashMap.remove(2); // remove the mapping for 2, The map is now [[1,1]]
myHashMap.get(2);    // return -1 (i.e., not found), The map is now [[1,1]]

Constraints:

• 0 <= key, value <= 106
• At most 104 calls will be made to put, get, and remove.

class MyHashMap {
public:
    vector<list<pair<int,int>>> data;
    size_t size = 10000;
    
    MyHashMap() {
        data.resize(size);
    }
    
    void put(int key, int value) {
        for (auto& e: data[key%size]) {
            if (e.first == key) {
                e.second = value;
                return;
            } 
        }
        data[key % size].push_back(make_pair(key, value));
    }
    
    int get(int key) {
        for (auto& e: data[key%size]) {
            if (e.first == key) {
                return e.second;
            } 
        }    
        return -1;
    }
    
    void remove(int key) {
        list<pair<int, int>>::iterator itr = data[key%size].begin();
        for (; itr != data[key%size].end(); itr++) {
            if (itr->first == key) {
                itr = data[key%size].erase(itr);
                return;
            } 
        }          
    }
};

Runtime: 134 ms, faster than 90.58% of C++ online submissions for Design HashMap.

Memory Usage: 62.1 MB, less than 59.69% of C++ online submissions for Design HashMap.