链式基数排序的中心思想是将每个关键字按一定的优先级分解成多个关键字,先按主关键字排序,再按次关键字排序,最后将结果再连接在一起。例如待排序数组如下:
305 403 417 922 429 78 7 20 446 23
可以先按个位数对其分组结果如下:
{20} {922} {403 23} {305} {446} {417 7} {78} {429}
再对十位数进行分组并将结果连接在一起:
{403 305} {7} {417} {20 922 23 429} {446} {78}
再对百位数进行分组并将结果连接在一起:
{7 20 23 78} {305} {403 417 429 446} {922}
实现的代码如下:
#include <stdio.h> #include <stdlib.h> #include <math.h> //数组大小 #define SIZE (10) //关键字级数 #define MAX_M (3) //空指针 #define null ((void *)(0)) //关键字结构 typedef struct s_rkey { int key; struct s_rkey *next; } s_rkey; //计算个位、十位、百位……的关键字值 int get_m_key(int key, int m) { m = pow(10, m); if (m == 10) { return key % m; } return (key % m) / (m / 10); } //链式基数排序 s_rkey* radix_link(s_rkey *header, s_rkey **p_rkey_s, s_rkey **p_rkey_e, int size, int m) { //头指针 s_rkey *p = header; s_rkey *p_temp = header; //按各个位上的关键字分别加入不同的链表中 while (p != null) { p_temp = p->next; p->next = null; //计算关键字 int k = get_m_key(p->key, m); if (p_rkey_e[k] == null) { p_rkey_s[k] = p; p_rkey_e[k] = p; } else { p_rkey_e[k]->next = p; p_rkey_e[k] = p_rkey_e[k]->next; } p = p_temp; } //将不同内容的关键字链表连接成一个链表 s_rkey *p_start = null; s_rkey *p_end = null; for (int i = 0; i < size; i++) { if (p_start == null && p_rkey_s[i] != null) { p_start = p_rkey_s[i]; p_end = p_rkey_e[i]; } else if (p_end != null && p_rkey_s[i] != null) { p_end->next = p_rkey_s[i]; p_end = p_rkey_e[i]; } } //置空 for (int i = 0; i < size; i++) { p_rkey_s[i] = null; p_rkey_e[i] = null; } //返回头节点 return p_start; } //基数排序 void radix_sort(int *array, int size) { //用于存放各个关键字的头尾指针 s_rkey **p_rkey_s = (s_rkey **) malloc(sizeof(s_rkey *) * size); s_rkey **p_rkey_e = (s_rkey **) malloc(sizeof(s_rkey *) * size); //初始化 for (int i = 0; i < size; i++) { p_rkey_s[i] = null; p_rkey_e[i] = null; } //头尾指针 s_rkey *p_start = null; s_rkey *p_end = null; for (int i = 0; i < size; i++) { //创建链表 s_rkey *p_rkey = (s_rkey *) malloc(sizeof(s_rkey)); p_rkey->key = array[i]; p_rkey->next = null; //记录头指针 if (p_start == null) { p_start = p_rkey; p_end = p_rkey; } //加入链表 else { p_end->next = p_rkey; p_end = p_end->next; } } //执行3次循环 for (int i = 0; i < MAX_M; i++) { //链式基数排序 p_start = radix_link(p_start, p_rkey_s, p_rkey_e, size, i + 1); //取得头节点 s_rkey *p = p_start; //显示结果 while (p != null) { printf("%d ", p->key); p = p->next; } printf("\n"); } //释放内存 s_rkey *p = p_start; while (p != null) { s_rkey *p_del = p; p = p->next; free(p_del); } //释放内存 free(p_rkey_s); free(p_rkey_e); } //显示数组 void display(int *array, int size) { for (int i = 0; i < size; i++) { printf("%d ", array[i]); } printf("\n"); } int main(int argc, char **args) { int array[SIZE] = { 305, 403, 417, 922, 429, 78, 7, 20, 446, 23 }; display(array, SIZE); radix_sort(array, SIZE); return 0; }
运行结果:
305 403 417 922 429 78 7 20 446 23 20 922 403 23 305 446 417 7 78 429 403 305 7 417 20 922 23 429 446 78 7 20 23 78 305 403 417 429 446 922
本例代码:
code path chapter.08/e.g.8.8/ https https://github.com/magicworldos/datastructure.git git git@github.com:magicworldos/datastructure.git subverion https://github.com/magicworldos/datastructure
Copyright © 2015-2023 问渠网 辽ICP备15013245号