Leetcode—706. 设计哈希映射【简单】（constexpr)

2024每日刷题（127）

Leetcode—706. 设计哈希映射

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数组实现代码

class MyHashMap {
public:
    MyHashMap() {
        memset(arr, -1, sizeof(arr));
    }
    
    void put(int key, int value) {
        arr[key] = value;
    }
    
    int get(int key) {
        if(arr[key] == -1) {
            return -1;
        } 
        return arr[key];
    }
    
    void remove(int key) {
        arr[key] = -1;
    }
private:
    int arr[1000001];
};

/**
 * 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);
 */

运行结果

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链地址法实现代码

class MyHashMap {
public:
    MyHashMap(): lists(kSize) {

    }
    
    void put(int key, int value) {
        auto &pairs = lists[key % kSize];
        for(auto &[k, v] : pairs) {
            if(k == key) {
                v = value;
                return;
            }
        }
        pairs.emplace_back(key, value);
    }
    
    int get(int key) {
        auto &pairs = lists[key % kSize];
        for(auto &[k, v] : pairs) {
            if(k == key) {
                return v;
            }
        }
        return -1;
    }
    
    void remove(int key) {
        auto &pairs = lists[key % kSize];
        for(auto it = pairs.begin(); it != pairs.end(); it++) {
            if(it->first == key) {
                pairs.erase(it);
                return;
            }
        }
    }
private:
    static constexpr int kSize = 10000;
    vector<list<pair<int, int>>> lists;
};

/**
 * 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);
 */