Sync LeetCode submission - Reverse Linked List (c)

Author: JMoogs

my-folder/problems/reverse_linked_list/solution.c

@@ -0,0 +1,38 @@
+struct ListNode* reverseList(struct ListNode* head) {
+	struct ListNode* prev = head;
+	if (!head) {
+		return 0;
+	}
+	struct ListNode* current = head->next;
+	if (!current) {
+		prev->next = 0;
+		return prev;
+	}
+	struct ListNode* next = current->next; 
+	if (!next) {
+		current->next = prev;
+		prev->next = 0;
+		return current;
+	}
+
+	prev->next = 0;
+	current->next = prev;
+
+	while (1) {
+		// Start state
+		// (0; NULL) (1; 0) (2; 3)
+		prev = current;
+		// (1; 0) (1; 0) (2; 3)
+		current = next;
+		// (1; 0) (2; 3) (2; 3)
+		next = next->next;
+		// (1; 0) (2; 3) (3; 4)
+		current->next = prev;
+		// End state
+		// (1; 0) (2; 1) (3; 4)
+		
+		if (!next) {
+			return current;
+		}
+	}
+}