目录
问题描述
设计一个不使用任何内置哈希表库的哈希集。 实现以下功能: 1.插入操作 2.移出操作 3.判断操作(判断是否含有关键字)
示例
MyHashSet hashSet = new MyHashSet();
hashSet.add(1);
hashSet.add(2);
hashSet.contains(1); // returns true
hashSet.contains(3); // returns false (not found)
hashSet.add(2); hashSet.contains(2); // returns true
hashSet.remove(2);
hashSet.contains(2); // returns false (already removed)
感想
这题如果没有思路的话可以参考以下代码,很容易理解 这里我主要要说明c语言和java的运行代码结果的比较(时间复杂度) 在代码中C语言要比java多写两个功能函数,分别是创建hash和释放hash表的操作, 原因在于java语言本身存在创建机制和自动回收机制,相对于c来说更加省时
代码
c:
typedef struct {
int key;
} MyHashSet;
/** Initialize your data structure here. */
MyHashSet* myHashSetCreate() {
MyHashSet* newhash=(MyHashSet*)malloc(sizeof(MyHashSet));
return newhash;
}
void myHashSetAdd(MyHashSet* obj, int key) {
obj[key].key=key;
}
void myHashSetRemove(MyHashSet* obj, int key) {
obj[key].key=NULL;
}
/** Returns true if this set contains the specified element */
bool myHashSetContains(MyHashSet* obj, int key) {
return obj[key].key==NULL ? false:true;
}
void myHashSetFree(MyHashSet* obj) {
free(obj);
}
/**
* Your MyHashSet struct will be instantiated and called as such:
* struct MyHashSet* obj = myHashSetCreate();
* myHashSetAdd(obj, key);
* myHashSetRemove(obj, key);
* bool param_3 = myHashSetContains(obj, key);
* myHashSetFree(obj);
*/
class MyHashSet {
Integer[] hash=new Integer[1000000];
/** Initialize your data structure here. */
public MyHashSet() {
}
public void add(int key) {
hash[key]=key;
}
public void remove(int key) {
hash[key]=null;
}
/** Returns true if this set contains the specified element */
public boolean contains(int key) {
return hash[key]==null?false:true;
}
}
/**
* Your MyHashSet object will be instantiated and called as such:
* MyHashSet obj = new MyHashSet();
* obj.add(key);
* obj.remove(key);
* boolean param_3 = obj.contains(key);
*/