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quick_sort.c
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quick_sort.c
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#include "quick_sort.h"
int _quick_sort_from_side_incremental (int cards[], size_t card_num)
{
size_t base;
if (card_num > 5){
base = random() % card_num;
}
else base = 0;
if (base) swap_int(cards, &cards[base]); //swap cards[0] and cards[base-1]
size_t base_final_pos = 0;
for (size_t i = 1; i <= card_num - 1; i++){
if (cards[i] < cards[0]){
base_final_pos++;
swap_int(&cards[base_final_pos], &cards[i]);
}
}
if (base_final_pos) swap_int(&cards[0], &cards[base_final_pos]);
size_t left_card_num, right_card_num;
left_card_num = base_final_pos;
right_card_num = card_num - left_card_num - 1;
if (left_card_num > K){
if (_quick_sort_from_side_incremental(cards, left_card_num)) return 2;
}else{
if (left_card_num > 1) _insert_sort_incremental(cards, left_card_num);
}
if (right_card_num > K){
if (_quick_sort_from_side_incremental(cards + base_final_pos + 1, right_card_num)) return 2;
}else{
if (right_card_num > 1) _insert_sort_incremental(cards + base_final_pos + 1, right_card_num);
}
return 0;
}
int _quick_sort_from_side_decremental (int cards[], size_t card_num)
{
size_t base;
if (card_num > 5){
time_t cur_time = time(NULL);
if (cur_time == (time_t)-1) return 1;
srandom((unsigned int)cur_time);
base = random() % card_num;
}
else base = 0;
swap_int(cards, &cards[base - 1]); //swap cards[0] and cards[base-1]
int base_final_pos = 0;
for (size_t i = 1; i <= card_num - 1; i++){
if (cards[i] > cards[0]){
base_final_pos++;
swap_int(&cards[base_final_pos], &cards[i]);
}
}
swap_int(&cards[0], &cards[base_final_pos]);
size_t left_card_num, right_card_num;
left_card_num = base_final_pos;
right_card_num = card_num - left_card_num - 1;
if (left_card_num > K){
if (_quick_sort_from_side_decremental(cards, left_card_num)) return 2;
}else{
if (left_card_num > 1) _insert_sort_decremental(cards, left_card_num);
}
if (right_card_num > K){
if (_quick_sort_from_side_decremental(cards + base_final_pos + 1, right_card_num)) return 2;
}else{
if (right_card_num > 1) _insert_sort_decremental(cards + base_final_pos + 1, right_card_num);
}
return 0;
}
int init_random (void)
{
struct timespec ts;
unsigned int rand;
if (clock_gettime(CLOCK_MONOTONIC, &ts) == -1) return 1;
rand = ts.tv_sec * ts.tv_nsec + ts.tv_sec + ts.tv_nsec;
srandom((unsigned int)rand);
return 0;
}
int quick_sort_from_side (int cards[], size_t card_num, int order)
{
if (cards == NULL || card_num == 0 || order == 0) return 1;
if (card_num == 1) return 0;
if (init_random()) return 2; //init_random(inner:clock_gettime) failed.
if (order > 0){
if (card_num == 2){
if (cards[0] > cards[1]) swap_int(&cards[0], &cards[1]);
}else if (card_num <= K) _insert_sort_incremental(cards, card_num);
else{
if (_quick_sort_from_side_incremental(cards, card_num)) return 3;
}
}else{
if (card_num == 2){
if (cards[0] < cards[1]) swap_int(&cards[0], &cards[1]);
}else if (card_num <= K) _insert_sort_decremental(cards, card_num);
else{
if (_quick_sort_from_side_decremental(cards, card_num)) return 4;
}
}
return 0;
}
/* test part */
/*
#include <stdio.h>
#include "assist.h"
int get_random_number (int *num, int max)
{
struct timespec ts;
unsigned int rand;
if (clock_gettime(CLOCK_MONOTONIC, &ts) == -1) return 1;
rand = ts.tv_sec * ts.tv_nsec + ts.tv_sec + ts.tv_nsec;
srandom(rand);
double f;
f = 1.0 * max * random() / (RAND_MAX + 1LL);
*num = f;
return 0;
}
int randomize_cards (int cards[], size_t card_num)
{
if (card_num == 1) return 0;
else if (card_num == 2){
swap_int(&cards[0], &cards[1]);
return 0;
}
static int previous1, previous2;
static int pos1, pos2;
long max = card_num / 2;
for (long int i = 0; i <= max; i++){
do{
previous1 = pos1;
previous2 = pos2;
if (get_random_number(&pos1, card_num)) return 1;
if (get_random_number(&pos2, card_num)) return 1;
if (pos1 > card_num - 1 || pos2 > card_num - 1) continue;
}while (pos1 == pos2 || (pos1 == previous1 && pos2 == previous2) || (pos1 == previous2 && pos2 == previous1));
swap_int(&cards[pos1], &cards[pos2]);
}
return 0;
}
void print_cards (int cards[], size_t card_num)
{
printf("cards:");
for (long int i = 0; i < card_num; i++) printf(" %d", cards[i]);
printf("\n");
}
int main (void)
{
int *cards = NULL;
int *orig_cards = NULL;
size_t card_num = 80;
if ((cards = malloc(sizeof(int) * card_num)) == NULL || (orig_cards = malloc(sizeof(int) * card_num)) == NULL) err("malloc failed.");
for (long i = 0; i < card_num; i++){
orig_cards[i] = i;
cards[i] = i;
}
if (randomize_cards (cards, card_num)) err("randomize failed.");
printf("original ");
print_cards(orig_cards, card_num);
printf("randomized ");
print_cards(cards, card_num);
if (quick_sort_from_side(cards, card_num, 1)) err("quick sort failed.");
for (long i = 0; i < card_num; i++){
if (cards[i] != orig_cards[i]){
printf("sort failed, cards[%ld]:%d, orig_cards[%ld]:%d.\n", i, cards[i], i, orig_cards[i]);
printf("sorted ");
print_cards(cards, card_num);
return 1;
}
}
printf("sort success.\n");
return 0;
}
*/