Array sort with qsort, by using two criteria?
Hello!
I already posted one question related to my quick sort problem, but since it is solved and I have a new one, I am starting a new thread. So I try to sort an array with qsort and then save the new order, so this means if I have a list like:
4 3 7 2
[0] [1] [2] [3],
after sorting it becomes:
2 3 4 7
[3] [1] [0] [2] <== this is what I want to have!
Which works fine, with following code:
Code:
void qsort_my(int *a, int l, int r, int *array_order) {
int j;
if( l < r ) {
j = split( a, l, r, array_order);
qsort_my( a, l, j-1, array_order);
qsort_my( a, j+1, r, array_order);
}
}
int split(int *a, int l, int r, int *array_order) {
int pivot, i, j, t;
pivot = a[l];
i = l; j = r+1;
int switch_pos_temp;
while (1) {
do ++i; while (a[i] >= pivot && i < r);
do --j; while (a[j] < pivot);
if (i >= j) break;
switch_pos(&a[i], &a[j]);
switch_pos(&array_order[i], &array_order[j]);
}
switch_pos(&a[l], &a[j]);
switch_pos(&array_order[l], &array_order[j]);
return j;
}
void switch_pos(int *one, int *two) {
int temp = *one;
*one = *two;
*two = temp;
}
Code:
#include <stdio.h>
#include <stdlib.h>
#include <dirent.h>
#include <string.h>
int main(int argc, char** argv) {
int tot = 10; int ini;
int*list;
list = malloc(sizeof(int)*tot);
list[0] = 4;list[1] = 8; list[2] = 14; list[3] = 1; list[4] = 2;
list[5] = 1;list[6] = 22; list[7] = 12; list[8] = 2; list[9] = 14;
int *array_ordered;
array_ordered = malloc(sizeof(int)*tot);
for(ini = 0; ini < tot; ini++) array_ordered[ini] = ini;
qsort_my(list, 0, tot-1, array_ordered);
free(list); free(array_ordered);
return 0;
}
But now I would like to add the second criteria: if two numbers of my list are equal, then I want the them to be sorted according to their position in array_ordered, which means if I have:
9 9
[0] [5]
They stay the same, but if they are like:
9 9
[5] [0]
i would like to swap them (for some reasons..doesnt matter why).
I tried to add the criteria : (if (a[i] != a[j] || (a[i] == a[j] && array_order[i] > array_order[j]))) before calling switch_pos, but it is not working since sometimes you swap two numbers like:
11 9 15 9 <= here the 11 and 15 are swapped,
but the two 9's will never be swapped <=> compared.
Does someone have some suggestion how could I do this?? I mean I could run it again with the array_order on the first parameter position, but this would increase my runtime enormously!
