Update Solution.c

Author: yanglbme

solution/0000-0099/0015.3Sum/Solution.c

@@ -1,50 +1,43 @@
-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** threeSum(int* nums, int numsSize, int* returnSize,
-    int** returnColumnSizes) {
+int** threeSum(int* nums, int numsSize, int* returnSize, int** returnColumnSizes) {
     *returnSize = 0;
-    int capacity = 100;
-    int** result = malloc(capacity * sizeof(int*));
-    int* colSizes = malloc(capacity * sizeof(int));
-    qsort(nums, numsSize, sizeof(int), cmp);
+    int cap = 1000;
+    int** ans = (int**) malloc(sizeof(int*) * cap);
+    *returnColumnSizes = (int*) malloc(sizeof(int) * cap);
 
-    for (int i = 0; i < numsSize - 2; i++) {
-        if (nums[i] > 0)
-            break;
-        if (i > 0 && nums[i] == nums[i - 1])
-            continue;
+    qsort(nums, numsSize, sizeof(int), cmp);
 
+    for (int i = 0; i < numsSize - 2 && nums[i] <= 0; ++i) {
+        if (i > 0 && nums[i] == nums[i - 1]) continue;
         int j = i + 1, k = numsSize - 1;
         while (j < k) {
             int sum = nums[i] + nums[j] + nums[k];
             if (sum < 0) {
-                j++;
+                ++j;
             } else if (sum > 0) {
-                k--;
+                --k;
             } else {
-                if (*returnSize >= capacity) {
-                    capacity *= 2;
-                    result = realloc(result, capacity * sizeof(int*));
-                    colSizes = realloc(colSizes, capacity * sizeof(int));
+                if (*returnSize >= cap) {
+                    cap *= 2;
+                    ans = (int**) realloc(ans, sizeof(int*) * cap);
+                    *returnColumnSizes = (int*) realloc(*returnColumnSizes, sizeof(int) * cap);
                 }
-
-                result[*returnSize] = malloc(3 * sizeof(int));
-                result[*returnSize][0] = nums[i];
-                result[*returnSize][1] = nums[j];
-                result[*returnSize][2] = nums[k];
-                colSizes[*returnSize] = 3;
+                ans[*returnSize] = (int*) malloc(sizeof(int) * 3);
+                ans[*returnSize][0] = nums[i];
+                ans[*returnSize][1] = nums[j];
+                ans[*returnSize][2] = nums[k];
+                (*returnColumnSizes)[*returnSize] = 3;
                 (*returnSize)++;
 
-                j++;
-                k--;
-                while (j < k && nums[j] == nums[j - 1])
-                    j++;
-                while (j < k && nums[k] == nums[k + 1])
-                    k--;
+                ++j;
+                --k;
+                while (j < k && nums[j] == nums[j - 1]) ++j;
+                while (j < k && nums[k] == nums[k + 1]) --k;
             }
         }
     }
-
-    *returnColumnSizes = colSizes;
-    return result;
+    return ans;
 }