Leetcode C语言算法刷题

 1#include <stdio.h>
 2#include <stdlib.h>
 3
 4int* twoSumNormal(int* nums, int numsSize, int target, int* returnSize);
 5
 6
 7int main(){
 8    int nums[4] = [2,7,11,15];
 9    int target = 9;
10    int* returnSize = 0;
11    int* res = twoSumNormal(nums, 4, target, returnSize);
12    free(res);
13    return 0;
14}
15
16
17//示例 1：
18//
19//输入：nums = [2,7,11,15], target = 9
20//输出：[0,1]
21//解释：因为 nums[0] + nums[1] == 9 ，返回 [0, 1] 。
22//示例 2：
23//
24//输入：nums = [3,2,4], target = 6
25//输出：[1,2]
26//示例 3：
27//
28//输入：nums = [3,3], target = 6
29//输出：[0,1]
30
31/**
32 * Note: The returned array must be malloced, assume caller calls free().
33 */
34int* twoSumNormal(int* nums, int numsSize, int target, int* returnSize) {
35    for (int i = 0; i < numsSize; i++) {
36        for (int j = i + 1; j < numsSize; ++j) {
37            if(nums[i] + nums[j] == target){
38                int* res = malloc(sizeof(int) * 2);
39                res[0] = i;
40                res[1] = j;
41                *returnSize = 2;
42                return res;
43            }
44        }
45    }
46
47    *returnSize = 0;
48    return NULL;
49}
50

 1#include "stdio.h"
 2#include "stdlib.h"
 3#include "uthash.h"
 4
 5//单个节点
 6struct hashTable {
 7    int key;
 8    int val;
 9    UT_hash_handle hh;
10};
11
12
13struct hashTable* find(int ikey);
14void insert(int ikey, int ival);
15int* twoSum(int* nums, int numsSize, int target, int* returnSize);
16
17
18//节点群
19static struct hashTable* hashtable;
20
21
22int main(){
23    return 0;
24}
25
26
27//从节点群中找到符合条件的单个节点, 如果找不到, 返回空
28struct hashTable* find(int ikey) {
29    struct hashTable* tmp;
30    HASH_FIND_INT(hashtable, &ikey, tmp);
31    return tmp;
32}
33
34void insert(int ikey, int ival) {
35    //检查是否是重复元素
36    struct hashTable* it = find(ikey);
37    if (it == NULL) {
38        struct hashTable* tmp = malloc(sizeof(struct hashTable));
39        tmp->key = ikey, tmp->val = ival;
40        HASH_ADD_INT(hashtable, ikey, tmp);
41    } else {
42        it->val = ival;
43    }
44}
45
46int* twoSum(int* nums, int numsSize, int target, int* returnSize) {
47    hashtable = NULL;
48    for (int i = 0; i < numsSize; i++) {
49        struct hashTable* it = find(target - nums[i]);
50        if (it != NULL) {
51            int* ret = malloc(sizeof(int) * 2);
52            ret[0] = it->val, ret[1] = i;
53            *returnSize = 2;
54            return ret;
55        }
56        insert(nums[i], i);
57    }
58    *returnSize = 0;
59    return NULL;
60}
61