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Signed-off-by: begeekmyfriend <begeekmyfriend@gmail.com>
1 parent 7afe0d9 commit b5ea034

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5 files changed

+63
-52
lines changed

5 files changed

+63
-52
lines changed

‎046_permutations/permutations.c

Lines changed: 24 additions & 13 deletions
Original file line numberDiff line numberDiff line change
@@ -10,32 +10,42 @@ static void swap(int *a, int *b)
1010
*b = tmp;
1111
}
1212

13-
static void dfs(int *nums, int size, int start, int **results, int *count)
13+
static void dfs(int *nums, int size, bool *used, int *stack,
14+
int len, int **results, int *count, int *col_size)
1415
{
1516
int i;
16-
if (start == size) {
17+
if (len == size) {
1718
results[*count] = malloc(size * sizeof(int));
18-
memcpy(results[*count], nums, size * sizeof(int));
19+
memcpy(results[*count], stack, size * sizeof(int));
20+
col_size[*count] = size;
1921
(*count)++;
2022
} else {
21-
for (i = start; i < size; i++) {
22-
swap(nums + start, nums + i);
23-
dfs(nums, size, start + 1, results, count);
24-
swap(nums + start, nums + i);
23+
for (i = 0; i < size; i++) {
24+
if (!used[i]) {
25+
used[i] = true;
26+
stack[len] = nums[i];
27+
dfs(nums, size, used, stack, len + 1, results, count, col_size);
28+
used[i] = false;
29+
}
2530
}
2631
}
2732
}
2833

2934
/**
30-
** Return an array of arrays of size *returnSize.
31-
** Note: The returned array must be malloced, assume caller calls free().
32-
**/
33-
static int **permute(int* nums, int numsSize, int* returnSize)
35+
* Return an array of arrays of size *returnSize.
36+
* The sizes of the arrays are returned as *returnColumnSizes array.
37+
* Note: Both returned array and *columnSizes array must be malloced, assume caller calls free().
38+
*/
39+
static int** permute(int* nums, int numsSize, int* returnSize, int** returnColumnSizes)
3440
{
3541
int count = 0, cap = 5000;
3642
int **results = malloc(cap * sizeof(int *));
43+
bool *used = malloc(numsSize * sizeof(bool));
44+
int *stack = malloc(numsSize * sizeof(int));
3745
*returnSize = 0;
38-
dfs(nums, numsSize, 0, results, returnSize);
46+
*returnColumnSizes = malloc(cap * sizeof(int));
47+
memset(used, false, numsSize * sizeof(bool));
48+
dfs(nums, numsSize, used, stack, 0, results, returnSize, *returnColumnSizes);
3949
return results;
4050
}
4151

@@ -52,7 +62,8 @@ int main(int argc, char **argv)
5262
nums[i] = atoi(argv[i + 1]);
5363
}
5464

55-
int **lists = permute(nums, argc - 1, &count);
65+
int *size;
66+
int **lists = permute(nums, argc - 1, &count, &size);
5667
for (i = 0; i < count; i++) {
5768
for (j = 0; j < argc - 1; j++) {
5869
printf("%d", lists[i][j]);

‎047_permutations_ii/permutations.c

Lines changed: 13 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -8,32 +8,34 @@ static int compare(const void *a, const void *b)
88
return *(int *) a - *(int *) b;
99
}
1010

11-
static void dfs(int *nums, int size, int *stack, int len,
12-
bool *used, int **results, int *count)
11+
static void dfs(int *nums, int size, bool *used, int *stack,
12+
int len, int **results, int *count, int *col_size)
1313
{
1414
int i;
1515
if (len == size) {
1616
results[*count] = malloc(len * sizeof(int));
1717
memcpy(results[*count], stack, len * sizeof(int));
18+
col_size[*count] = size;
1819
(*count)++;
1920
} else {
2021
for (i = 0; i < size; i++) {
2122
if (!used[i]) {
2223
if (i > 0 && nums[i] == nums[i - 1] && !used[i - 1]) continue;
2324
used[i] = true;
2425
stack[len] = nums[i];
25-
dfs(nums, size, stack, len + 1, used, results, count);
26+
dfs(nums, size, used, stack, len + 1, results, count, col_size);
2627
used[i] = false;
2728
}
2829
}
2930
}
3031
}
3132

3233
/**
33-
** Return an array of arrays of size *returnSize.
34-
** Note: The returned array must be malloced, assume caller calls free().
35-
**/
36-
static int **permute(int* nums, int numsSize, int* returnSize)
34+
* Return an array of arrays of size *returnSize.
35+
* The sizes of the arrays are returned as *returnColumnSizes array.
36+
* Note: Both returned array and *columnSizes array must be malloced, assume caller calls free().
37+
*/
38+
static int **permute(int* nums, int numsSize, int* returnSize, int **returnColumnSize)
3739
{
3840
qsort(nums, numsSize, sizeof(int), compare);
3941

@@ -43,7 +45,8 @@ static int **permute(int* nums, int numsSize, int* returnSize)
4345
bool *used = malloc(numsSize);
4446
memset(used, false, numsSize);
4547
*returnSize = 0;
46-
dfs(nums, numsSize, stack, 0, used, results, returnSize);
48+
*returnColumnSize = malloc(cap * sizeof(int));
49+
dfs(nums, numsSize, used, stack, 0, results, returnSize, *returnColumnSize);
4750
return results;
4851
}
4952

@@ -58,10 +61,10 @@ int main(int argc, char **argv)
5861
int *nums = malloc(count * sizeof(int));
5962
for (i = 0; i < count; i++) {
6063
nums[i] = atoi(argv[i + 1]);
61-
printf("%d\n", nums[i]);
6264
}
6365

64-
int **lists = permute(nums, argc - 1, &count);
66+
int *size;
67+
int **lists = permute(nums, argc - 1, &count, &size);
6568
for (i = 0; i < count; i++) {
6669
for (j = 0; j < argc - 1; j++) {
6770
printf("%d", lists[i][j]);

‎077_combinations/combinations.c

Lines changed: 9 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -4,7 +4,7 @@
44
#include <string.h>
55

66
static void dfs(int n, int k, int start, int *stack, int len,
7-
bool *used, int *col_sizes, int **results, int *count)
7+
int **results, int *count, int *col_sizes)
88
{
99
int i;
1010
if (len == k) {
@@ -14,30 +14,25 @@ static void dfs(int n, int k, int start, int *stack, int len,
1414
(*count)++;
1515
} else {
1616
for (i = start; i <= n; i++) {
17-
if (!used[i]) {
18-
stack[len] = i;
19-
used[i] = true;
20-
dfs(n, k, i + 1, stack, len + 1, used, col_sizes, results, count);
21-
used[i] = false;
22-
}
17+
/* No used marks since the order does not matter */
18+
stack[len] = i;
19+
dfs(n, k, i + 1, stack, len + 1, results, count, col_sizes);
2320
}
2421
}
2522
}
2623

2724
/**
2825
* Return an array of arrays of size *returnSize.
29-
* The sizes of the arrays are returned as *columnSizes array.
26+
* The sizes of the arrays are returned as *returnColumnSizes array.
3027
* Note: Both returned array and *columnSizes array must be malloced, assume caller calls free().
3128
*/
32-
int** combine(int n, int k, int** columnSizes, int* returnSize) {
29+
int** combine(int n, int k, int* returnSize, int** returnColumnSizes) {
3330
int capacity = 10000;
3431
int count = 0;
3532
int **results = malloc(capacity * sizeof(int *));
3633
int *stack = malloc(k * sizeof(int));
37-
bool *used = malloc((n + 1) * sizeof(bool));
38-
memset(used, false, n + 1);
39-
*columnSizes = malloc(capacity * sizeof(int));
40-
dfs(n, k, 1, stack, 0, used, *columnSizes, results, &count);
34+
*returnColumnSizes = malloc(capacity * sizeof(int));
35+
dfs(n, k, 1, stack, 0, results, &count, *returnColumnSizes);
4136
*returnSize = count;
4237
return results;
4338
}
@@ -50,7 +45,7 @@ int main(int argc, char **argv)
5045
}
5146

5247
int i, j, *col_sizes, count = 0;
53-
int **lists = combine(atoi(argv[1]), atoi(argv[2]), &col_sizes, &count);
48+
int **lists = combine(atoi(argv[1]), atoi(argv[2]), &count, &col_sizes);
5449
for (i = 0; i < count; i++) {
5550
for (j = 0; j < col_sizes[i]; j++) {
5651
printf("%d ", lists[i][j]);

‎078_subsets/subsets.c

Lines changed: 7 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -3,7 +3,7 @@
33
#include <string.h>
44

55
static void dfs(int *nums, int size, int start, int *buf,
6-
int len, int **sets, int *sizes, int *count)
6+
int len, int **sets, int *count, int *sizes)
77
{
88
int i;
99
sets[*count] = malloc(len * sizeof(int));
@@ -12,23 +12,23 @@ static void dfs(int *nums, int size, int start, int *buf,
1212
(*count)++;
1313
for (i = start; i < size; i++) {
1414
buf[len] = nums[i];
15-
dfs(nums, size, i + 1, buf, len + 1, sets, sizes, count);
15+
dfs(nums, size, i + 1, buf, len + 1, sets, count, sizes);
1616
}
1717
}
1818

1919
/**
2020
** Return an array of arrays of size *returnSize.
21-
** The sizes of the arrays are returned as *columnSizes array.
21+
** The sizes of the arrays are returned as *returnColumnSizes array.
2222
** Note: Both returned array and *columnSizes array must be malloced, assume caller calls free().
2323
**/
24-
int** subsets(int* nums, int numsSize, int** columnSizes, int* returnSize)
24+
int** subsets(int* nums, int numsSize, int* returnSize, int** returnColumnSizes)
2525
{
2626
int capacity = 5000;
2727
int **sets = malloc(capacity * sizeof(int *));
2828
int *buf = malloc(numsSize * sizeof(int));
29-
*columnSizes = malloc(capacity * sizeof(int));
29+
*returnColumnSizes = malloc(capacity * sizeof(int));
3030
*returnSize = 0;
31-
dfs(nums, numsSize, 0, buf, 0, sets, *columnSizes, returnSize);
31+
dfs(nums, numsSize, 0, buf, 0, sets, returnSize, *returnColumnSizes);
3232
return sets;
3333
}
3434

@@ -46,7 +46,7 @@ int main(int argc, char **argv)
4646
}
4747
int *sizes;
4848
int count;
49-
int **lists = subsets(nums, size, &sizes, &count);
49+
int **lists = subsets(nums, size, &count, &sizes);
5050
for (i = 0; i < count; i++) {
5151
for (j = 0; j < sizes[i]; j++) {
5252
printf("%d ", lists[i][j]);

‎090_subsets_ii/subsets.c

Lines changed: 10 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -9,7 +9,7 @@ static inline int compare(const void *a, const void *b)
99
}
1010

1111
static void dfs(int *nums, int size, int start, int *buf, int level,
12-
bool *used, int **sets, int *sizes, int *count)
12+
bool *used, int **sets, int *count, int *sizes)
1313
{
1414
int i;
1515
sets[*count] = malloc(level * sizeof(int));
@@ -18,31 +18,33 @@ static void dfs(int *nums, int size, int start, int *buf, int level,
1818
(*count)++;
1919
for (i = start; i < size; i++) {
2020
if (!used[i]) {
21-
if (i > 0 && !used[i - 1] && nums[i - 1] == nums[i]) continue;
21+
if (i > 0 && !used[i - 1] && nums[i - 1] == nums[i]) {
22+
continue;
23+
}
2224
used[i] = true;
2325
buf[level] = nums[i];
24-
dfs(nums, size, i + 1, buf, level + 1, used, sets, sizes, count);
26+
dfs(nums, size, i + 1, buf, level + 1, used, sets, count, sizes);
2527
used[i] = false;
2628
}
2729
}
2830
}
2931

3032
/**
3133
** Return an array of arrays of size *returnSize.
32-
** The sizes of the arrays are returned as *columnSizes array.
34+
** The sizes of the arrays are returned as *returnColumnSizes array.
3335
** Note: Both returned array and *columnSizes array must be malloced, assume caller calls free().
3436
**/
35-
static int** subsets(int* nums, int numsSize, int** columnSizes, int* returnSize)
37+
static int** subsets(int* nums, int numsSize, int* returnSize, int** returnColumnSizes)
3638
{
3739
qsort(nums, numsSize, sizeof(int), compare);
3840
int capacity = 5000;
3941
int **sets = malloc(capacity * sizeof(int *));
4042
int *buf = malloc(numsSize * sizeof(int));
4143
bool *used = malloc(numsSize);
4244
memset(used, false, numsSize);
43-
*columnSizes = malloc(capacity * sizeof(int));
45+
*returnColumnSizes = malloc(capacity * sizeof(int));
4446
*returnSize = 0;
45-
dfs(nums, numsSize, 0, buf, 0, used, sets, *columnSizes, returnSize);
47+
dfs(nums, numsSize, 0, buf, 0, used, sets, returnSize, *returnColumnSizes);
4648
return sets;
4749
}
4850

@@ -60,7 +62,7 @@ int main(int argc, char **argv)
6062
}
6163
int *sizes;
6264
int count;
63-
int **lists = subsets(nums, size, &sizes, &count);
65+
int **lists = subsets(nums, size, &count, &sizes);
6466
for (i = 0; i < count; i++) {
6567
for (j = 0; j < sizes[i]; j++) {
6668
printf("%d ", lists[i][j]);

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