Rust數據結構和算法系列[4]-鏈式哈希表

 

//鏈式哈希表，將數據存在桶中
struct chtbale{
    buckets : i32, //桶的個數
    size : i32, //數據數量
    table : Vec<Option<Vec<i32>>>, //哈希表
}
impl chtbale{
    fn hashfunc(&self,data:i32) -> i32{ //哈希函數
        return data  % self.buckets;
    }
    fn lookup(&self,data:i32) -> bool{
        let bucket :i32 = self.hashfunc(data);
        let optionlst  = self.table[bucket as usize].as_ref();
        if let Some(lists) = optionlst{
            if lists.contains(&data){
                return true;
            }
        }
        return false;
    }
    pub fn new(buckets:i32) -> Self{ //初始化桶的數量
        let mut tt :Vec<Option<Vec<i32>>> = Vec::new();
        for _ in 0..buckets{ 
            tt.push(Some(Vec::new()));
        }
        Self{
            buckets:buckets,
            size : 0,
            table : tt,
        }
    }
    pub fn insert(&mut self,data:i32){
        if self.lookup(data) == true{
            return; 
        }
        let bucket :i32 = self.hashfunc(data);
        
        self.table[bucket as usize].as_mut().unwrap().push(data);
        self.size += 1;
    }
    pub fn remove(&mut self,data:i32){
        if self.lookup(data) == false{
            return; 
        }
        let bucket :i32 = self.hashfunc(data);
        let optionlst = self.table[bucket as usize].as_mut();
        if let Some(lists) = optionlst{
            for i in 0..lists.len(){
                if lists[i] == data{
                    lists.remove(i);
                    self.size -= 1;
                }
            }
        }
    }
}
pub fn run(){
    let mut myhash = chtbale::new(10);
    for i in 0..255{
        myhash.insert(i);
    }
    myhash.remove(250);
    for i in 0..10{
        println!("{:?}",myhash.table[i]);
    }
    
}

運行結果如下