Merge branch 'main' of https://github.com/pranjal030404/leetcode.doocs

Author: pranjal030404

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

@@ -317,30 +317,33 @@ 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;
+```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/0000-0099/0016.3Sum Closest/README_EN.md

@@ -316,30 +316,33 @@ 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;
+```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/0000-0099/0016.3Sum Closest/Solution.c

@@ -1,23 +1,26 @@
-
-int cmp(const void* a, const void* b) { return *(int*) a - *(int*) b; }
+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 ans = 1 << 30;
+    for (int i = 0; i < numsSize; ++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;
+            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;
             }
-            if (sum < target)
-                j++;
-            else
-                k--;
         }
     }
-
-    return closest;
+    return ans;
 }

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

@@ -557,35 +557,44 @@ 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);
-  }
-}
+```c
+char* d[] = {"abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz"};
 
-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;
-}
+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/0000-0099/0017.Letter Combinations of a Phone Number/README_EN.md

@@ -553,35 +553,44 @@ 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);
-  }
-}
+```c
+char* d[] = {"abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz"};
 
-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;
-}
+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/0000-0099/0017.Letter Combinations of a Phone Number/Solution.c

@@ -1,27 +1,37 @@
-char* map[] = {"", "", "abc", "def", "ghi",
-    "jkl", "mno", "pqrs", "tuv", "wxyz"};
+char* d[] = {"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;
+char** letterCombinations(char* digits, int* returnSize) {
+    if (!*digits) {
+        *returnSize = 0;
+        return NULL;
     }
-    for (char* p = map[d[i] - '0']; *p; p++) {
-        cur[i] = *p;
-        backtrack(d, i + 1, cur, res, sz);
+
+    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;
     }
-}
 
-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;
+    *returnSize = size;
+    return ans;
 }