On 9/8/25 1:10 PM, Alex Hung wrote:
On 8/24/25 12:23, Kuan-Wei Chiu wrote:
Replace the previous O(N^2) implementation of remove_duplicates() in
with a O(N) version using a fast/slow pointer approach. The new version
keeps only the first occurrence of each element and compacts the array
in place, improving efficiency without changing functionality.
Signed-off-by: Kuan-Wei Chiu <visitor...@gmail.com>
---
Verified correctness using the following simple unit test:
double arr1[] = {1,1,2,2,3}; int size1=5;
remove_duplicates(arr1,&size1);
assert(size1==3 && arr1[0]==1 && arr1[1]==2 && arr1[2]==3);
double arr2[] = {1,2,3}; int size2=3;
remove_duplicates(arr2,&size2);
assert(size2==3 && arr2[0]==1 && arr2[1]==2 && arr2[2]==3);
double arr3[] = {5,5,5,5}; int size3=4;
remove_duplicates(arr3,&size3);
assert(size3==1 && arr3[0]==5);
double arr4[] = {}; int size4=0;
remove_duplicates(arr4,&size4);
assert(size4==0);
.../dc/dml2/dml21/src/dml2_pmo/dml2_pmo_dcn3.c | 18 ++++++++----------
1 file changed, 8 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/dc/dml2/dml21/src/dml2_pmo/
dml2_pmo_dcn3.c b/drivers/gpu/drm/amd/display/dc/dml2/dml21/src/
dml2_pmo/dml2_pmo_dcn3.c
index 2b13a5e88917..5100e0e7af42 100644
--- a/drivers/gpu/drm/amd/display/dc/dml2/dml21/src/dml2_pmo/
dml2_pmo_dcn3.c
+++ b/drivers/gpu/drm/amd/display/dc/dml2/dml21/src/dml2_pmo/
dml2_pmo_dcn3.c
@@ -50,18 +50,16 @@ static void
set_reserved_time_on_all_planes_with_stream_index(struct display_con
static void remove_duplicates(double *list_a, int *list_a_size)
{
- int cur_element = 0;
- // For all elements b[i] in list_b[]
- while (cur_element < *list_a_size - 1) {
- if (list_a[cur_element] == list_a[cur_element + 1]) {
- for (int j = cur_element + 1; j < *list_a_size - 1; j++) {
- list_a[j] = list_a[j + 1];
- }
- *list_a_size = *list_a_size - 1;
- } else {
- cur_element++;
+ int j = 0;
+
+ for (int i = 1; i < *list_a_size; i++) {
+ if (list_a[j] != list_a[i]) {
+ j++;
+ list_a[j] = list_a[i];
}
}
+
+ *list_a_size = j + 1;
A corner case needs fixing:
When input *list_a_size is zero, it will be updated to 1, unlike the
original code. Maybe a early return when *list_a_size is zero?
Hi Aurabindo,
Do you have other comments or other concerns?
Patch looks good with the early return added. Only nit is the
description wording - an extraneous 'in' is present.
--
Thanks & Regards,
Aurabindo Pillai
