0002 Solution in c language

solution/0000-0099/0001.Two Sum/README.md

@@ -353,6 +353,55 @@ class Solution {
 }
 ```
 
+#### C
+
+```c
+#include <stdlib.h>
+
+int* twoSum(int* nums, int numsSize, int target, int* returnSize) {
+    int capacity = 1;
+    while (capacity < numsSize * 2) capacity <<= 1;
+    int* keys = malloc(capacity * sizeof(int));
+    int* vals = malloc(capacity * sizeof(int));
+    char* used = calloc(capacity, sizeof(char));
+    if (!keys || !vals || !used) {
+        free(keys);
+        free(vals);
+        free(used);
+        *returnSize = 0;
+        return NULL;
+    }
+    for (int i = 0; i < numsSize; ++i) {
+        int x = nums[i];
+        int y = target - x;
+        unsigned int h = (unsigned int) y & (capacity - 1);
+        while (used[h]) {
+            if (keys[h] == y) {
+                int* res = malloc(2 * sizeof(int));
+                res[0] = vals[h];
+                res[1] = i;
+                *returnSize = 2;
+                free(keys);
+                free(vals);
+                free(used);
+                return res;
+            }
+            h = (h + 1) & (capacity - 1);
+        }
+        unsigned int h2 = (unsigned int) x & (capacity - 1);
+        while (used[h2]) h2 = (h2 + 1) & (capacity - 1);
+        used[h2] = 1;
+        keys[h2] = x;
+        vals[h2] = i;
+    }
+    *returnSize = 0;
+    free(keys);
+    free(vals);
+    free(used);
+    return NULL;
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

solution/0000-0099/0001.Two Sum/README_EN.md

@@ -350,6 +350,55 @@ class Solution {
 }
 ```
 
+#### C
+
+```c
+#include <stdlib.h>
+
+int* twoSum(int* nums, int numsSize, int target, int* returnSize) {
+    int capacity = 1;
+    while (capacity < numsSize * 2) capacity <<= 1;
+    int* keys = malloc(capacity * sizeof(int));
+    int* vals = malloc(capacity * sizeof(int));
+    char* used = calloc(capacity, sizeof(char));
+    if (!keys || !vals || !used) {
+        free(keys);
+        free(vals);
+        free(used);
+        *returnSize = 0;
+        return NULL;
+    }
+    for (int i = 0; i < numsSize; ++i) {
+        int x = nums[i];
+        int y = target - x;
+        unsigned int h = (unsigned int) y & (capacity - 1);
+        while (used[h]) {
+            if (keys[h] == y) {
+                int* res = malloc(2 * sizeof(int));
+                res[0] = vals[h];
+                res[1] = i;
+                *returnSize = 2;
+                free(keys);
+                free(vals);
+                free(used);
+                return res;
+            }
+            h = (h + 1) & (capacity - 1);
+        }
+        unsigned int h2 = (unsigned int) x & (capacity - 1);
+        while (used[h2]) h2 = (h2 + 1) & (capacity - 1);
+        used[h2] = 1;
+        keys[h2] = x;
+        vals[h2] = i;
+    }
+    *returnSize = 0;
+    free(keys);
+    free(vals);
+    free(used);
+    return NULL;
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

solution/0000-0099/0001.Two Sum/Solution.c

@@ -0,0 +1,44 @@
+#include <stdlib.h>
+
+int* twoSum(int* nums, int numsSize, int target, int* returnSize) {
+    int capacity = 1;
+    while (capacity < numsSize * 2) capacity <<= 1;
+    int* keys = malloc(capacity * sizeof(int));
+    int* vals = malloc(capacity * sizeof(int));
+    char* used = calloc(capacity, sizeof(char));
+    if (!keys || !vals || !used) {
+        free(keys);
+        free(vals);
+        free(used);
+        *returnSize = 0;
+        return NULL;
+    }
+    for (int i = 0; i < numsSize; ++i) {
+        int x = nums[i];
+        int y = target - x;
+        unsigned int h = (unsigned int) y & (capacity - 1);
+        while (used[h]) {
+            if (keys[h] == y) {
+                int* res = malloc(2 * sizeof(int));
+                res[0] = vals[h];
+                res[1] = i;
+                *returnSize = 2;
+                free(keys);
+                free(vals);
+                free(used);
+                return res;
+            }
+            h = (h + 1) & (capacity - 1);
+        }
+        unsigned int h2 = (unsigned int) x & (capacity - 1);
+        while (used[h2]) h2 = (h2 + 1) & (capacity - 1);
+        used[h2] = 1;
+        keys[h2] = x;
+        vals[h2] = i;
+    }
+    *returnSize = 0;
+    free(keys);
+    free(vals);
+    free(used);
+    return NULL;
+}

solution/0000-0099/0002.Add Two Numbers/README.md

@@ -494,6 +494,57 @@ proc addTwoNumbers(l1: var SinglyLinkedList, l2: var SinglyLinkedList): SinglyLi
   result = aggregate
 ```
 
+#### C
+
+```c
+/**
+ * Definition for singly-linked list.
+ * struct ListNode {
+ *     int val;
+ *     struct ListNode *next;
+ * };
+ */
+
+struct ListNode *addTwoNumbers(struct ListNode *l1, struct ListNode *l2)
+{
+    struct ListNode *dummy = (struct ListNode *)malloc(sizeof(struct ListNode));
+    dummy->val = 0;
+    dummy->next = NULL;
+    struct ListNode *curr = dummy;
+    int carry = 0;
+
+    while (l1 != NULL || l2 != NULL || carry != 0)
+    {
+        int sum = carry;
+        if (l1 != NULL)
+        {
+            sum += l1->val;
+            l1 = l1->next;
+        }
+        if (l2 != NULL)
+        {
+            sum += l2->val;
+            l2 = l2->next;
+        }
+
+        carry = sum / 10;
+        int val = sum % 10;
+
+        struct ListNode *newNode = (struct ListNode *)malloc(sizeof(struct ListNode));
+        newNode->val = val;
+        newNode->next = NULL;
+        curr->next = newNode;
+        curr = curr->next;
+    }
+
+    struct ListNode *result = dummy->next;
+    free(dummy); 
+    return result;
+}
+
+```
+
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

solution/0000-0099/0002.Add Two Numbers/README_EN.md

@@ -490,6 +490,55 @@ proc addTwoNumbers(l1: var SinglyLinkedList, l2: var SinglyLinkedList): SinglyLi
   result = aggregate
 ```
 
+#### C
+
+```c
+/**
+ * Definition for singly-linked list.
+ * struct ListNode {
+ *     int val;
+ *     struct ListNode *next;
+ * };
+ */
+
+struct ListNode *addTwoNumbers(struct ListNode *l1, struct ListNode *l2)
+{
+    struct ListNode *dummy = (struct ListNode *)malloc(sizeof(struct ListNode));
+    dummy->val = 0;
+    dummy->next = NULL;
+    struct ListNode *curr = dummy;
+    int carry = 0;
+
+    while (l1 != NULL || l2 != NULL || carry != 0)
+    {
+        int sum = carry;
+        if (l1 != NULL)
+        {
+            sum += l1->val;
+            l1 = l1->next;
+        }
+        if (l2 != NULL)
+        {
+            sum += l2->val;
+            l2 = l2->next;
+        }
+
+        carry = sum / 10;
+        int val = sum % 10;
+
+        struct ListNode *newNode = (struct ListNode *)malloc(sizeof(struct ListNode));
+        newNode->val = val;
+        newNode->next = NULL;
+        curr->next = newNode;
+        curr = curr->next;
+    }
+
+    struct ListNode *result = dummy->next;
+    free(dummy); 
+    return result;
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

solution/0000-0099/0002.Add Two Numbers/Solution.c

@@ -0,0 +1,40 @@
+/**
+ * Definition for singly-linked list.
+ * struct ListNode {
+ *     int val;
+ *     struct ListNode *next;
+ * };
+ */
+
+struct ListNode* addTwoNumbers(struct ListNode* l1, struct ListNode* l2) {
+    struct ListNode* dummy = (struct ListNode*) malloc(sizeof(struct ListNode));
+    dummy->val = 0;
+    dummy->next = NULL;
+    struct ListNode* curr = dummy;
+    int carry = 0;
+
+    while (l1 != NULL || l2 != NULL || carry != 0) {
+        int sum = carry;
+        if (l1 != NULL) {
+            sum += l1->val;
+            l1 = l1->next;
+        }
+        if (l2 != NULL) {
+            sum += l2->val;
+            l2 = l2->next;
+        }
+
+        carry = sum / 10;
+        int val = sum % 10;
+
+        struct ListNode* newNode = (struct ListNode*) malloc(sizeof(struct ListNode));
+        newNode->val = val;
+        newNode->next = NULL;
+        curr->next = newNode;
+        curr = curr->next;
+    }
+
+    struct ListNode* result = dummy->next;
+    free(dummy);
+    return result;
+}