王道数据结构 （23） 基数排序

 

 示例代码 ：

/**
 * 基数排序-单链表实现
 */

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define Error(Str) FatalError(Str)
#define FatalError(Str) fprintf(stderr, "%s
", Str), exit(1)

#define N 10      //数个数
#define RADIX 10  //基数
#define POS_LEN 3 //位长

typedef struct Node
{
  int data;
  struct Node *next;
} * pNode;
typedef pNode LNode;

pNode create();
int get_num_pos(int num, int pos, int radix);
void radix_sort(pNode collect, int radix, int pos_len);
void append_node(pNode L, int num);
void insert(pNode P, int num);
void delete_list(pNode L);
void test();
void print(pNode L);

int main(void)
{
  test();
  return 0;
}

void radix_sort(pNode collect, int radix, int pos_len)
{
  // collect assign
  LNode assign[radix - 1], P, tmp, p;
  int i, num;
  for (i = 0; i < radix; i++)
  {
    assign[i] = create();
  }
  for (i = 1; i <= pos_len; i++)
  {
    P = collect;
    while (NULL != P->next)
    {
      p = P->next;
      P->next = p->next;
      p->next = NULL;
      int num = get_num_pos(p->data, i, radix);
      tmp = assign[num];
      while (NULL != tmp->next)
      {
        tmp = tmp->next;
      }
      tmp->next = p;
    }
    printf("第%d次分配
", i);
    for (int j = 0; j < radix; j++)
    {
      printf("N-%d	", j);
      print(assign[j]);
    }

    //assign
    P = collect;
    for (int j = 0; j < radix; j++)
    {
      LNode phead;
      phead = assign[j];
      while (NULL != phead->next)
      {
        p = phead->next;
        phead->next = p->next;
        p->next = NULL;
        P->next = p;
        P = P->next;
      }
    }
    printf("第%d次收集
", i);
    print(collect);
    // 置空
    // for (int j = 0; j < radix; j++) {
    //  delete_list(assign[j]);
    // }
  }
  // free space
  for (i = 0; i < radix; i++)
  {
    delete_list(assign[i]);
  }
}

int get_num_pos(int num, int pos, int radix)
{
  int temp = 1, i;
  for (i = 0; i < pos - 1; i++)
    temp *= radix;
  return (num / temp) % radix;
}
void insert(pNode P, int num)
{
  pNode temp;
  temp = (pNode)malloc(sizeof(struct Node));
  if (NULL == temp)
    FatalError("out of space");
  temp->data = num;
  temp->next = NULL;
  P->next = temp;
}

void append_node(pNode L, int num)
{
  pNode temp, P;
  P = L;
  temp = (pNode)malloc(sizeof(struct Node));
  if (NULL == temp)
    FatalError("out of space");
  temp->next = NULL;

  while (NULL != P->next)
  {
    P = P->next;
  }
  P->next = temp;
}

pNode create()
{
  pNode L;
  L = (pNode)malloc(sizeof(struct Node));
  if (NULL == L)
    FatalError("out of space");
  L->next = NULL;
  return L;
}

void delete_list(pNode L)
{
  pNode P, temp;
  P = L->next;
  L->next = NULL;
  while (NULL != P)
  {
    temp = P->next;
    free(P);
    P = temp;
  }
}

void print(pNode L)
{
  pNode P;
  P = L->next;
  while (NULL != P)
  {
    printf("%d	", P->data);
    P = P->next;
  }
  printf("
");
}

void test()
{
  pNode source, tmp, P;
  int arr[N] = {
      278,
      109,
      63,
      930,
      589,
      184,
      505,
      269,
      8,
      83};
  int i;
  int max = 1;
  for (i = 0; i <= POS_LEN - 1; i++)
    max *= RADIX;
  source = create();
  P = source;
  srand((unsigned)time(NULL));
  for (i = 0; i < N; i++)
  {
    insert(P, arr[i]);
    P = P->next;
  }
  print(source);
  radix_sort(source, RADIX, POS_LEN);
  printf("结果
");
  print(source);
}

运行结果 ：