拉链法解决冲突。拉链法解决冲突的做法是将所有的相同Hash值的key放在一个链表中,比如key3和key14在hash之后都是0,那么在数组的键为0的地方存储这两个值,形式是链表。如果不能理解我的文字,请看下面的示例,看一下打印信息就明白了。拉链法是什么,就是链表。
class HashNode{
public $key;
public $value;
public $nextNode;
public function __construct($key, $value, $nextNode=Null){
$this->key = $key;
$this->value = $value;
$this->nextNode = $nextNode;
}
}
class HashTable{
private $arr;
private $size=10;
public function __construct(){
$this->arr = new SplFixedArray($this->size);
} public function SimpleHash($key){
$ascTotal=0;
$strlen = strlen($key);
for($i=0;$i<$strlen;$i++){
$ascTotal+=ord($key[$i]);
}
return $ascTotal%$this->size;
}
//使用拉链法
//将最新的放在前面
public function set($key,$val){
$hash = $this->SimpleHash($key);
if(isset($this->arr[$hash])){
$newNode = new HashNode($key,$val,$this->arr[$hash]);
}else{
$newNode= new HashNode($key,$val,null);
}
$this->arr[$hash] = $newNode;
return true;
} public function get($key){
$hash = $this->SimpleHash($key);
$current = $this->arr[$hash];
while(!empty($current)){
if($current->key == $key ){
return $current->value;
}
$current = $current->nextNode;
}
return NULL;
}
public function getList(){
return $this->arr;
}
}
$newArr = new HashTable();
for($i=0;$i<25;$i++){
$key = 'key'.$i;
$newArr->set($key,$i);
}
$arr = $newArr->getList();
print_r($arr);