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Two sum
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Signed-off-by: begeekmyfriend <[email protected]>
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begeekmyfriend committed Jul 12, 2017
1 parent 0a8d29d commit 3b66491
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2 changes: 2 additions & 0 deletions 001_two_sum/Makefile
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all:
gcc -O2 -o test two_sum.c
261 changes: 104 additions & 157 deletions 001_two_sum/two_sum.c
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/*
* Copyright (C) 2015, Leo Ma <[email protected]>
*/

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

struct hlist_node;

struct hlist_head
{
struct hlist_node *first;
struct hlist_head {
struct hlist_node *first;
};

struct hlist_node
{
struct hlist_node *next, **pprev;
struct hlist_node {
struct hlist_node *next, **pprev;
};

static inline void
INIT_HLIST_HEAD(struct hlist_head *h)
{
h->first = NULL;
}

static inline void
INIT_HLIST_NODE(struct hlist_node *n)
{
n->next = NULL;
n->pprev = NULL;
}

static inline int
hlist_unhashed(struct hlist_node *n)
{
return !n->pprev;
static inline void INIT_HLIST_HEAD(struct hlist_head *h) {
h->first = NULL;
}

static inline int
hlist_empty(struct hlist_head *h)
{
return !h->first;
static inline void INIT_HLIST_NODE(struct hlist_node *n) {
n->next = NULL;
n->pprev = NULL;
}

static inline void
hlist_add_head(struct hlist_node *n, struct hlist_head *h)
{
if (h->first != NULL) {
h->first->pprev = &n->next;
}
n->next = h->first;
n->pprev = &h->first;
h->first = n;
static inline int hlist_empty(struct hlist_head *h) {
return !h->first;
}

static inline void
__hlist_del(struct hlist_node *n)
static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
{
struct hlist_node *next = n->next;
struct hlist_node **pprev = n->pprev;
*pprev = next;
if (next != NULL) {
next->pprev = pprev;
}
if (h->first != NULL) {
h->first->pprev = &n->next;
}
n->next = h->first;
n->pprev = &h->first;
h->first = n;
}

static inline void
hlist_del(struct hlist_node *n)
static inline void hlist_del(struct hlist_node *n)
{
__hlist_del(n);
}

static inline void
hlist_add_before(struct hlist_node *n, struct hlist_node *next)
{
n->next = next;
n->pprev = next->pprev;
*(n->pprev) = n;
next->pprev = &n->next;
}

static inline void
hlist_add_behind(struct hlist_node *n, struct hlist_node *prev)
{
struct hlist_node *next = prev->next;
n->next = next;
prev->next = n;
n->pprev = &prev->next;
if (next != NULL) {
next->pprev = &n->next;
}
struct hlist_node *next = n->next;
struct hlist_node **pprev = n->pprev;
*pprev = next;
if (next != NULL) {
next->pprev = pprev;
}
}

#define container_of(ptr, type, member) \
((type *)((char *)(ptr) - (size_t)&(((type *)0)->member)))
((type *)((char *)(ptr) - (size_t)&(((type *)0)->member)))

#define hlist_entry(ptr, type, member) \
container_of(ptr, type, member)
container_of(ptr, type, member)

#define hlist_for_each(pos, head) \
for (pos = (head)->first; pos; pos = pos->next)
for (pos = (head)->first; pos; pos = pos->next)

#define hlist_for_each_safe(pos, n, head) \
for (pos = (head)->first; pos && ({ n = pos->next; true; }); pos = n)
for (pos = (head)->first; pos && ({ n = pos->next; true; }); pos = n)

int *
twosum(int numbers[], int n, int target)
static int * twosum(int *nums, int numsSize, int target)
{
int i, j;
struct hash_table
{
struct hlist_head h;
};
struct plus_elem
{
int index;
int num;
struct hlist_node n;
};

struct hash_table *ht = malloc(n * sizeof(*ht));
if (ht == NULL) {
return NULL;
}
for (i = 0; i < n; i++) {
INIT_HLIST_HEAD(&ht[i].h);
}
struct plus_elem *elems = malloc(n * sizeof(*elems));
if (elems == NULL) {
return NULL;
}
for (i = 0; i < n; i++) {
elems[i].num = 0;
INIT_HLIST_NODE(&elems[i].n);
struct hash_table {
struct hlist_head head;
};
struct plus_elem {
int index;
int num;
struct hlist_node node;
};

int i, j;
struct hash_table *ht = malloc(numsSize * sizeof(*ht));
for (i = 0; i < numsSize; i++) {
INIT_HLIST_HEAD(&ht[i].head);
}

struct plus_elem *elems = malloc(numsSize * sizeof(*elems));
for (i = 0; i < numsSize; i++) {
elems[i].num = 0;
INIT_HLIST_NODE(&elems[i].node);
}

for (i = 0; i < numsSize; i++) {
int num = nums[i] < 0 ? -nums[i] : nums[i];
int hash = num % numsSize;
elems[i].index = i;
elems[i].num = nums[i];
hlist_add_head(&elems[i].node, &ht[hash].head);
}

for (i = 0; i < numsSize; i++) {
int num = target - nums[i];
int h1 = nums[i] < 0 ? -nums[i] % numsSize : nums[i] % numsSize;
int h2 = num < 0 ? -num % numsSize : num % numsSize;
int i1 = -1, i2 = -1;
struct hlist_node *pos;
hlist_for_each(pos, &ht[h1].head) {
struct plus_elem *elem = hlist_entry(pos, struct plus_elem, node);
if (elem->num == nums[i]) {
i1 = elem->index;
break;
}
}

for (i = 0; i < n; i++) {
int num = numbers[i] < 0 ? -numbers[i] : numbers[i];
int hash = num % n;
elems[i].index = i + 1;
elems[i].num = numbers[i];
hlist_add_head(&elems[i].n, &ht[hash].h);
hlist_for_each(pos, &ht[h2].head) {
struct plus_elem *elem = hlist_entry(pos, struct plus_elem, node);
if (elem->num == num) {
if (i1 != elem->index) {
i2 = elem->index;
break;
}
}
}

for (i = 0; i < n; i++) {
int num = target - numbers[i];
int h1 = numbers[i] < 0 ? -numbers[i] % n : numbers[i] % n;
int h2 = num < 0 ? -num % n : num % n;
int i1 = 0, i2 = 0;
struct hlist_node *pos;
hlist_for_each(pos, &ht[h1].h) {
struct plus_elem *elem = hlist_entry(pos, struct plus_elem, n);
if (elem->num == numbers[i]) {
i1 = elem->index;
break;
}
}
hlist_for_each(pos, &ht[h2].h) {
struct plus_elem *elem = hlist_entry(pos, struct plus_elem, n);
if (elem->num == num) {
if (i1 != elem->index) {
i2 = elem->index;
break;
}
}
}
if (i1 > 0 && i2 > 0) {
int *indexes = malloc(2 * sizeof(int));
if (indexes == NULL) {
break;
}
indexes[0] = i1 < i2 ? i1 : i2;
indexes[1] = i1 > i2 ? i1 : i2;
return indexes;
}
if (i1 >= 0 && i2 >= 0) {
int *indexes = malloc(2 * sizeof(int));
if (indexes == NULL) {
break;
}
indexes[0] = i1 < i2 ? i1 : i2;
indexes[1] = i1 > i2 ? i1 : i2;
return indexes;
}
}

return NULL;
return NULL;
}

int
main(void)
int main(void)
{
//int numbers[] = {-1, -2, -3, -4, -5};
//int target = -8;
int numbers[] = {0,4,3,0};
int target = 0;
int *indexes = twosum(numbers, sizeof(numbers) / sizeof(numbers[0]), target);
if (indexes != NULL) {
printf("%d %d\n", indexes[0], indexes[1]);
} else {
printf("Not found\n");
}

return 0;
//int nums[] = {-1, -2, -3, -4, -5};
//int target = -8;
//int nums[] = {0,4,3,0};
//int target = 0;
int nums[] = { 3, 2, 4 };
int target = 6;
int *indexes = twosum(nums, sizeof(nums) / sizeof(nums[0]), target);
if (indexes != NULL) {
printf("%d %d\n", indexes[0], indexes[1]);
} else {
printf("Not found\n");
}

return 0;
}

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