feat: add c solutions to lc problems: No.0016,0017 (#4544)

Author: pranjal030404

solution/0000-0099/0016.3Sum Closest/README.md

@@ -315,6 +315,37 @@ class Solution {
 }
 ```
 
+#### C
+
+```c
+int cmp(const void* a, const void* b) {
+    return (*(int*) a - *(int*) b);
+}
+
+int threeSumClosest(int* nums, int numsSize, int target) {
+    qsort(nums, numsSize, sizeof(int), cmp);
+    int ans = 1 << 30;
+    for (int i = 0; i < numsSize; ++i) {
+        int j = i + 1, k = numsSize - 1;
+        while (j < k) {
+            int t = nums[i] + nums[j] + nums[k];
+            if (t == target) {
+                return t;
+            }
+            if (abs(t - target) < abs(ans - target)) {
+                ans = t;
+            }
+            if (t > target) {
+                --k;
+            } else {
+                ++j;
+            }
+        }
+    }
+    return ans;
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

solution/0000-0099/0016.3Sum Closest/README_EN.md

@@ -314,6 +314,37 @@ class Solution {
 }
 ```
 
+#### C
+
+```c
+int cmp(const void* a, const void* b) {
+    return (*(int*) a - *(int*) b);
+}
+
+int threeSumClosest(int* nums, int numsSize, int target) {
+    qsort(nums, numsSize, sizeof(int), cmp);
+    int ans = 1 << 30;
+    for (int i = 0; i < numsSize; ++i) {
+        int j = i + 1, k = numsSize - 1;
+        while (j < k) {
+            int t = nums[i] + nums[j] + nums[k];
+            if (t == target) {
+                return t;
+            }
+            if (abs(t - target) < abs(ans - target)) {
+                ans = t;
+            }
+            if (t > target) {
+                --k;
+            } else {
+                ++j;
+            }
+        }
+    }
+    return ans;
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

solution/0000-0099/0016.3Sum Closest/Solution.c

@@ -0,0 +1,26 @@
+int cmp(const void* a, const void* b) {
+    return (*(int*) a - *(int*) b);
+}
+
+int threeSumClosest(int* nums, int numsSize, int target) {
+    qsort(nums, numsSize, sizeof(int), cmp);
+    int ans = 1 << 30;
+    for (int i = 0; i < numsSize; ++i) {
+        int j = i + 1, k = numsSize - 1;
+        while (j < k) {
+            int t = nums[i] + nums[j] + nums[k];
+            if (t == target) {
+                return t;
+            }
+            if (abs(t - target) < abs(ans - target)) {
+                ans = t;
+            }
+            if (t > target) {
+                --k;
+            } else {
+                ++j;
+            }
+        }
+    }
+    return ans;
+}

solution/0000-0099/0017.Letter Combinations of a Phone Number/README.md

@@ -555,6 +555,48 @@ class Solution {
 }
 ```
 
+#### C
+
+```c
+char* d[] = {"abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz"};
+
+char** letterCombinations(char* digits, int* returnSize) {
+    if (!*digits) {
+        *returnSize = 0;
+        return NULL;
+    }
+
+    int size = 1;
+    char** ans = (char**) malloc(sizeof(char*));
+    ans[0] = strdup("");
+
+    for (int x = 0; digits[x]; ++x) {
+        char* s = d[digits[x] - '2'];
+        int len = strlen(s);
+        char** t = (char**) malloc(sizeof(char*) * size * len);
+        int tSize = 0;
+
+        for (int i = 0; i < size; ++i) {
+            for (int j = 0; j < len; ++j) {
+                int oldLen = strlen(ans[i]);
+                char* tmp = (char*) malloc(oldLen + 2);
+                strcpy(tmp, ans[i]);
+                tmp[oldLen] = s[j];
+                tmp[oldLen + 1] = '\0';
+                t[tSize++] = tmp;
+            }
+            free(ans[i]);
+        }
+        free(ans);
+        ans = t;
+        size = tSize;
+    }
+
+    *returnSize = size;
+    return ans;
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

solution/0000-0099/0017.Letter Combinations of a Phone Number/README_EN.md

@@ -551,6 +551,48 @@ class Solution {
 }
 ```
 
+#### C
+
+```c
+char* d[] = {"abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz"};
+
+char** letterCombinations(char* digits, int* returnSize) {
+    if (!*digits) {
+        *returnSize = 0;
+        return NULL;
+    }
+
+    int size = 1;
+    char** ans = (char**) malloc(sizeof(char*));
+    ans[0] = strdup("");
+
+    for (int x = 0; digits[x]; ++x) {
+        char* s = d[digits[x] - '2'];
+        int len = strlen(s);
+        char** t = (char**) malloc(sizeof(char*) * size * len);
+        int tSize = 0;
+
+        for (int i = 0; i < size; ++i) {
+            for (int j = 0; j < len; ++j) {
+                int oldLen = strlen(ans[i]);
+                char* tmp = (char*) malloc(oldLen + 2);
+                strcpy(tmp, ans[i]);
+                tmp[oldLen] = s[j];
+                tmp[oldLen + 1] = '\0';
+                t[tSize++] = tmp;
+            }
+            free(ans[i]);
+        }
+        free(ans);
+        ans = t;
+        size = tSize;
+    }
+
+    *returnSize = size;
+    return ans;
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

solution/0000-0099/0017.Letter Combinations of a Phone Number/Solution.c

@@ -0,0 +1,37 @@
+char* d[] = {"abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz"};
+
+char** letterCombinations(char* digits, int* returnSize) {
+    if (!*digits) {
+        *returnSize = 0;
+        return NULL;
+    }
+
+    int size = 1;
+    char** ans = (char**) malloc(sizeof(char*));
+    ans[0] = strdup("");
+
+    for (int x = 0; digits[x]; ++x) {
+        char* s = d[digits[x] - '2'];
+        int len = strlen(s);
+        char** t = (char**) malloc(sizeof(char*) * size * len);
+        int tSize = 0;
+
+        for (int i = 0; i < size; ++i) {
+            for (int j = 0; j < len; ++j) {
+                int oldLen = strlen(ans[i]);
+                char* tmp = (char*) malloc(oldLen + 2);
+                strcpy(tmp, ans[i]);
+                tmp[oldLen] = s[j];
+                tmp[oldLen + 1] = '\0';
+                t[tSize++] = tmp;
+            }
+            free(ans[i]);
+        }
+        free(ans);
+        ans = t;
+        size = tSize;
+    }
+
+    *returnSize = size;
+    return ans;
+}