Refine

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

Author: begeekmyfriend

021_merge_two_sorted_lists/merge_lists.c

@@ -12,7 +12,7 @@ static struct ListNode* mergeTwoLists(struct ListNode* l1, struct ListNode* l2)
     struct ListNode *prev = &dummy;
     dummy.next = l1;
 
-    while (l1 != NULL || l2 != NULL) {
+    while (l1 != NULL && l2 != NULL) {
         if (l1->val <= l2->val) {
             prev = l1;
             l1 = l1->next;

239_sliding_window_maximum/slide_window.c

@@ -13,16 +13,19 @@ int* maxSlidingWindow(int* nums, int numsSize, int k, int* returnSize)
     int *results = malloc((numsSize - k + 1) * sizeof(int));
 
     for (i = 0; i < numsSize; i++) {
-        /* monotonous decreasing */
+        /* keep the elements in slide window monotonous decreasing */
         while (tail > head && nums[i] >= nums[indexes[tail - 1]]) {
+            /* squeeze out the previous smaller ones */
             tail--;
         }
-        indexes[tail++] = i;
 
+        /* Pipe: first in last out */
+        indexes[tail++] = i;
         if (indexes[head] <= i - k) {
             head++;
         }
 
+        /* k - 1 is the end of the first sliding window */
         if (i >= k - 1) {
             results[count++] = nums[indexes[head]];
         }