Solution of 0016 and 0017 done in c language

Author: pranjal030404

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

@@ -315,6 +315,34 @@ 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 closest = nums[0] + nums[1] + nums[2];
+
+  for (int i = 0; i < numsSize - 2; i++) {
+    int j = i + 1, k = numsSize - 1;
+    while (j < k) {
+      int sum = nums[i] + nums[j] + nums[k];
+      if (abs(sum - target) < abs(closest - target)) {
+        closest = sum;
+      }
+      if (sum < target)
+        j++;
+      else
+        k--;
+    }
+  }
+
+  return closest;
+}
+
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

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

@@ -314,6 +314,34 @@ 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 closest = nums[0] + nums[1] + nums[2];
+
+  for (int i = 0; i < numsSize - 2; i++) {
+    int j = i + 1, k = numsSize - 1;
+    while (j < k) {
+      int sum = nums[i] + nums[j] + nums[k];
+      if (abs(sum - target) < abs(closest - target)) {
+        closest = sum;
+      }
+      if (sum < target)
+        j++;
+      else
+        k--;
+    }
+  }
+
+  return closest;
+}
+
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

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

@@ -0,0 +1,23 @@
+
+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 closest = nums[0] + nums[1] + nums[2];
+
+    for (int i = 0; i < numsSize - 2; i++) {
+        int j = i + 1, k = numsSize - 1;
+        while (j < k) {
+            int sum = nums[i] + nums[j] + nums[k];
+            if (abs(sum - target) < abs(closest - target)) {
+                closest = sum;
+            }
+            if (sum < target)
+                j++;
+            else
+                k--;
+        }
+    }
+
+    return closest;
+}

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

@@ -555,6 +555,39 @@ class Solution {
 }
 ```
 
+#### C
+
+``` C
+char *map[] = {"",    "",    "abc",  "def", "ghi",
+               "jkl", "mno", "pqrs", "tuv", "wxyz"};
+
+void backtrack(char *d, int i, char *cur, char **res, int *sz) {
+  if (!d[i]) {
+    res[(*sz)++] = strdup(cur);
+    return;
+  }
+  for (char *p = map[d[i] - '0']; *p; p++) {
+    cur[i] = *p;
+    backtrack(d, i + 1, cur, res, sz);
+  }
+}
+
+char **letterCombinations(char *d, int *sz) {
+  *sz = 0;
+  if (!*d)
+    return NULL;
+  int max = 1, len = strlen(d);
+  for (int i = 0; i < len; i++)
+    max *= (d[i] == '7' || d[i] == '9') ? 4 : 3;
+  char **res = malloc(max * sizeof(char *)), *cur = malloc(len + 1);
+  cur[len] = '\0';
+  backtrack(d, 0, cur, res, sz);
+  free(cur);
+  return res;
+}
+
+```
+
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 <!-- solution:end -->

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

@@ -551,6 +551,39 @@ class Solution {
 }
 ```
 
+#### C
+
+``` C
+char *map[] = {"",    "",    "abc",  "def", "ghi",
+               "jkl", "mno", "pqrs", "tuv", "wxyz"};
+
+void backtrack(char *d, int i, char *cur, char **res, int *sz) {
+  if (!d[i]) {
+    res[(*sz)++] = strdup(cur);
+    return;
+  }
+  for (char *p = map[d[i] - '0']; *p; p++) {
+    cur[i] = *p;
+    backtrack(d, i + 1, cur, res, sz);
+  }
+}
+
+char **letterCombinations(char *d, int *sz) {
+  *sz = 0;
+  if (!*d)
+    return NULL;
+  int max = 1, len = strlen(d);
+  for (int i = 0; i < len; i++)
+    max *= (d[i] == '7' || d[i] == '9') ? 4 : 3;
+  char **res = malloc(max * sizeof(char *)), *cur = malloc(len + 1);
+  cur[len] = '\0';
+  backtrack(d, 0, cur, res, sz);
+  free(cur);
+  return res;
+}
+
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

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

@@ -0,0 +1,27 @@
+char* map[] = {"", "", "abc", "def", "ghi",
+    "jkl", "mno", "pqrs", "tuv", "wxyz"};
+
+void backtrack(char* d, int i, char* cur, char** res, int* sz) {
+    if (!d[i]) {
+        res[(*sz)++] = strdup(cur);
+        return;
+    }
+    for (char* p = map[d[i] - '0']; *p; p++) {
+        cur[i] = *p;
+        backtrack(d, i + 1, cur, res, sz);
+    }
+}
+
+char** letterCombinations(char* d, int* sz) {
+    *sz = 0;
+    if (!*d)
+        return NULL;
+    int max = 1, len = strlen(d);
+    for (int i = 0; i < len; i++)
+        max *= (d[i] == '7' || d[i] == '9') ? 4 : 3;
+    char **res = malloc(max * sizeof(char*)), *cur = malloc(len + 1);
+    cur[len] = '\0';
+    backtrack(d, 0, cur, res, sz);
+    free(cur);
+    return res;
+}