Mirror
/
cpython
mirror of https://github.com/python/cpython
4
1
Fork 0
Code Issues Releases Wiki Activity

Quicksort retuned by Tim Peters.

This commit is contained in:
Guido van Rossum 1998-04-28 13:17:56 +00:00
parent bee64533d6
commit 82e6a8f80d
1 changed files with 26 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

59
Objects/listobject.c
View File

@ -634,7 +634,7 @@ static int
insertionsort(array, size, compare)
PyObject **array; /* Start of array to sort */
int size; /* Number of elements to sort */
PyObject *compare;/* Comparison function object, or NULL for default */
PyObject *compare;/* Comparison function object, or NULL => default */
{
register PyObject **a = array;
register PyObject **end = array+size;
@ -645,6 +645,8 @@ insertionsort(array, size, compare)
register PyObject **q = p;
while (--q >= a) {
register int k = docompare(*q, key, compare);
/* if (p-q >= MINSIZE)
fprintf(stderr, "OUCH! %d\n", p-q); */
if (k == CMPERROR)
return -1;
if (k <= 0)
@ -703,7 +705,7 @@ quicksort(array, size, compare)
n = hi - lo;
if (n < MINSIZE) {
/*
* skip it. The insertion sort at the end will
* skip it. The insertion sort at the end will
* catch these
*/
continue;
@ -733,11 +735,14 @@ quicksort(array, size, compare)
{ tmp = *l; *l = *lo; *lo = tmp; }
pivot = *l;
/* Move pivot off to the side (swap with lo+1) */
*l = *(lo+1); *(lo+1) = pivot;
/* Partition the array */
l = lo+1;
l = lo+2;
r = hi-2;
for (;;) {
/* Move left index to element > pivot */
do {
/* Move left index to element >= pivot */
while (l < hi) {
k = docompare(*l, pivot, compare);
if (k == CMPERROR)
@ -746,8 +751,8 @@ quicksort(array, size, compare)
break;
l++;
}
/* Move right index to element < pivot */
while (r >= lo) {
/* Move right index to element <= pivot */
while (r > lo) {
k = docompare(pivot, *r, compare);
if (k == CMPERROR)
return -1;
@ -756,21 +761,17 @@ quicksort(array, size, compare)
r--;
}
/* If they met, we're through */
if (l < r) {
/* If they crossed, we're through */
if (l <= r) {
/* Swap elements and continue */
tmp = *l; *l = *r; *r = tmp;
l++; r--;
}
else if (l == r) {
l++; r--;
break;
}
if (l > r)
break;
}
} while (l <= r);
/* Swap pivot back into place; *r <= pivot */
*(lo+1) = *r; *r = pivot;
/* We have now reached the following conditions:
lo <= r < l <= hi
@ -785,27 +786,19 @@ quicksort(array, size, compare)
n2 = hi - l;
if (n > n2) {
/* First one is bigger */
if (n > MINSIZE) {
lostack[top] = lo;
histack[top++] = r;
if (n2 > MINSIZE) {
lostack[top] = l;
histack[top++] = hi;
}
}
lostack[top] = lo;
histack[top++] = r;
lostack[top] = l;
histack[top++] = hi;
} else {
/* Second one is bigger */
if (n2 > MINSIZE) {
lostack[top] = l;
histack[top++] = hi;
if (n > MINSIZE) {
lostack[top] = lo;
histack[top++] = r;
}
}
lostack[top] = l;
histack[top++] = hi;
lostack[top] = lo;
histack[top++] = r;
}
/* Should assert top < STACKSIZE-1 */
/* Should assert top <= STACKSIZE */
}
/*