Update comments

Signed-off-by: begeekmyfriend <[email protected]>

Author: begeekmyfriend

0015_three_sum/three_sum.c

@@ -31,7 +31,7 @@ static void two_sum(int *nums, int low, int high, int target, int **results, int
  ** Return an array of arrays of size *returnSize.
  ** Note: The returned array must be malloced, assume caller calls free().
  **/
-int** threeSum(int* nums, int numsSize, int* returnSize)
+int** threeSum(int* nums, int numsSize, int* returnSize, int** returnColumnSizes)
 {
     if (numsSize < 3) {
         return NULL;
@@ -47,6 +47,12 @@ int** threeSum(int* nums, int numsSize, int* returnSize)
             two_sum(nums, i + 1, numsSize - 1, -nums[i], results, returnSize);
         }
     }
+
+    *returnColumnSizes = malloc(*returnSize * sizeof(int *));
+    for (i = 0; i < *returnSize; i++) {
+        (*returnColumnSizes)[i] = 3;
+    }
+
     return results;
 }
 

0018_four_sum/four_sum.c

@@ -8,8 +8,8 @@ static int compare(const void *a, const void *b)
     return *(int *) a - *(int *) b;
 }
 
-static void k_sum(int *nums, int low, int high, int target, int total, int k, 
-                  int *stack, int len, int **results, int *count, int *col_sizes)
+static void k_sum(int *nums, int low, int high, long target, int total, int k, 
+                  int *stack, int len, int **results, int *count)
 {
     int i;
     if (k == 2) {
@@ -24,7 +24,6 @@ static void k_sum(int *nums, int low, int high, int target, int total, int k,
                 stack[len++] = nums[high];
                 results[*count] = malloc(total * sizeof(int));
                 memcpy(results[*count], stack, total * sizeof(int));
-                col_sizes[*count] = total;
                 (*count)++;
                 len -= 2;
                 while (++low < high && nums[low] == nums[low - 1]) {}
@@ -36,7 +35,8 @@ static void k_sum(int *nums, int low, int high, int target, int total, int k,
         for (i = low; i <= high - k + 1; i++) {
             if (i > low && nums[i] == nums[i - 1]) continue;
             stack[len] = nums[i];
-            k_sum(nums, i + 1, high, target - nums[i], 4, k - 1, stack, len + 1, results, count, col_sizes);
+            k_sum(nums, i + 1, high, target - nums[i], 4, k - 1, stack,
+                  len + 1, results, count);
         }
     }
 }
@@ -49,15 +49,20 @@ static void k_sum(int *nums, int low, int high, int target, int total, int k,
 int** fourSum(int* nums, int numsSize, int target, int* returnSize, int** returnColumnSizes)
 {
     *returnSize = 0;
-    int i, j, capacity = 50000;
+    int i, capacity = 50000;
     int **results = malloc(capacity * sizeof(int *));
-    *returnColumnSizes = malloc(capacity * sizeof(int));
 
     if (numsSize >= 4) {
         qsort(nums, numsSize, sizeof(*nums), compare);
         int *stack = malloc(4 * sizeof(int));
-        k_sum(nums, 0, numsSize - 1, target, 4, 4, stack, 0, results, returnSize, *returnColumnSizes);
+        k_sum(nums, 0, numsSize - 1, target, 4, 4, stack, 0, results, returnSize);
     }
+
+    *returnColumnSizes = malloc(capacity * sizeof(int));
+    for (i = 0; i < *returnSize; i++) {
+        (*returnColumnSizes)[i] = 4;
+    }
+
     return results;
 }
 

0031_next_permutation/next_permutation.cc

@@ -5,21 +5,17 @@ using namespace std;
 class Solution {
 public:
     void nextPermutation(vector<int>& nums) {
-        if (nums.size() < 2) {
-            return;
-        }
-
         int i = nums.size() - 2;
         while (i >= 0 && nums[i] >= nums[i + 1]) {
             i--;
         }
 
         if (i >= 0) {
             int j = nums.size() - 1;
-            while (j >= 0 && nums[j] >= nums[i]) {
+            while (j >= 0 && nums[i] >= nums[j]) {
                 j--;
             }
-            swap(nums.begin() + i, nums.begin() + j);
+            swap(nums[i], nums[j]);
         }
 
         reverse(nums.begin() + i + 1, nums.end());

0167_two_sum_ii/two_sum.c

@@ -9,14 +9,14 @@ static int* twoSum(int* numbers, int numbersSize, int target, int* returnSize)
 {
     int i = 0, j = numbersSize - 1;
     while (i < j) {
-        int diff = target - numbers[i] - numbers[j];
-        if (diff > 0) {
+        int sum = numbers[i] + numbers[j];
+        if (sum < target) {
             i++;
-        } else if (diff < 0) {
+        } else if (sum > target) {
             j--;
         } else {
             *returnSize = 2;
-            int *indexes = malloc(*returnSize * sizeof(int));
+            int *indexes = malloc(2 * sizeof(int));
             indexes[0] = i + 1;
             indexes[1] = j + 1;
             return indexes;

0167_two_sum_ii/two_sum.cc

@@ -9,10 +9,10 @@ class Solution {
         int i = 0;
         int j = numbers.size() - 1;
         while (i < j) {
-            int diff = target - numbers[i] - numbers[j];
-            if (diff > 0) {
+            int sum = numbers[i] + numbers[j];
+            if (sum < target) {
                 i++;
-            } else if (diff < 0) {
+            } else if (sum > target) {
                 j--;
             } else {
                 res.push_back(i + 1);