开放地址法散列表ADT

数据结构定义如下：

 typedef unsigned int Index;
 typedef Index Position;

 struct HashTbl;
 typedef struct HashTbl *HashTable;

 HashTable InitializeTable(int TableSize);
 void DestroyTable(HashTable H);
 Position Find(ElementType Key, HashTable H);
 void Insert(ElementType Key, HashTable H);
 ElementType Retrieve(Position P, HashTable H);
 HashTable Rehash(HashTable H);

 enum KindOfEntry {Legitimate, Empty, Deleted};
 struct HashEntry{
     ElementType Element;
     enum KindOfEntry Info;
 };
 typedef struct HashEntry Cell;

 struct HashTbl{
     int TableSize;
     Cell *TheCells;
 };

初始化函数代码如下：

 HashTable InitializeTable(int TableSize){
     HashTable H;
     int i;

     if(TableSize < MinTableSize){
         printf("Table size too small\n");
         return NULL;
     }

     H = malloc(sizeof(struct HashTbl));
     H->TableSize = NextPrime(TableSize);
     H->TheCells = malloc(H->TableSize * sizeof(Cell));

     for(i=; i<H->TableSize; i++)
         H->TheCells[i].Info = Empty;

     return H;
 }

Find函数实现代码如下：

 Position Find(ElementType Key, HashTable H){
     Position Pos;
     int i;

     i=;
     Pos = Hash(Key, H->TableSize);
     while(H->TheCells[Pos].Info != Empty
         && H->TheCells[Pos].Element != Key){
             Pos += (++i)*-;
             if(Pos >= H->TableSize)
                 Pos -= H->TableSize;
     }
     return Pos;
 }

Insert函数代码实现如下：

 void Insert(ElementType Key, HashTable H){
     Position Pos;
     Pos = Find(Key, H);
     if(H->TheCells[Pos].Info != Legitimate){
         H->TheCells[Pos].Info = Legitimate;
         H->TheCells[Pos].Element = Key;
     }
 }

Rehash函数代码实现如下：

 HashTable rehash(HashTable H){
     int i, OldSize = H->TableSize;
     HashTable OldH = H;
     Cell *OldCells = H->TheCells;

     H = InitializeTable(*OldSize);
     for(int i=; i<OldSize; i++){
         if(OldCells[i].Info == Legitimate)
             Insert(OldCells[i].Element, H);
     }

     free(OldH);
     free(OldCells);
     return H;
 }