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begeekmyfriend · begeekmyfriend · commit f583b444508d · 2020-06-14T09:57:48.000+08:00
Signed-off-by: begeekmyfriend &lt;begeekmyfriend@gmail.com&gt;
diff --git a/061_rotate_list/rotate_list.c b/061_rotate_list/rotate_list.c
@@ -6,41 +6,40 @@ struct ListNode {
     struct ListNode *next;
 };
 
-static struct ListNode* rotateRight(struct ListNode* head, int k) {
+static struct ListNode* rotateRight(struct ListNode* head, int k)
+{
     if (head == NULL || k <= 0) {
         return head;
     }
 
     struct ListNode dummy;
     dummy.next = head;
     struct ListNode *prev = &dummy;
-    struct ListNode *last = &dummy;
     struct ListNode *p = head;
-    int count = k;
-    while (k > 0) {
-        if (p == NULL) {
-            int length = count - k;
-            prev = &dummy;
-            p = head;
-            k = count % length;
-            if (k == 0) break;
-        }
+    int len = 0;
+    while (p != NULL) {
         prev = p;
         p = p->next;
-        k--;
+        len++;
     }
 
-    while (p != NULL) {
-        last = last->next;
+    struct ListNode *last = prev;
+    prev = &dummy;
+    p = head;
+    len = len - (k % len);
+    while (len-- > 0) {
         prev = p;
         p = p->next;
     }
 
-    if (last != &dummy) {
-        prev->next = head;
-        dummy.next = last->next;
-        last->next = NULL;
+    if (p != NULL) {
+        /* deletion */
+        prev->next = NULL;
+        /* insertion */
+        last->next = dummy.next;
+        dummy.next = p;
     }
+
     return dummy.next;
 }
 
@@ -59,13 +58,11 @@ int main(int argc, char **argv)
     for (i = 2; i < argc; i++) {
         p = malloc(sizeof(*p));
         int n = atoi(argv[i]);
-        printf("%d ", n);
         p->val = n;
         p->next = NULL;
         prev->next = p;
         prev = p;
     }
-    putchar('\n');
 
     list = rotateRight(dummy.next, atoi(argv[1]));
     for (p = list; p != NULL; p = p->next) {
