week7

Author: YeonguChoe

reverse-linked-list/yeonguchoe.c

@@ -0,0 +1,25 @@
+/**
+ * Definition for singly-linked list.
+ * struct ListNode {
+ *     int val;
+ *     struct ListNode *next;
+ * };
+ */
+struct ListNode* reverseList(struct ListNode* head) {
+
+    struct ListNode* ptr1 = NULL;
+    struct ListNode* ptr2 = head;
+    struct ListNode* ptr3 = NULL;
+
+    while (ptr2 != NULL) {
+        ptr3 = ptr2->next;
+        ptr2->next = ptr1;
+
+        // 앞으로 전진
+        ptr1 = ptr2;
+        ptr2 = ptr3;
+    }
+    return ptr1;
+}
+// 시간 복잡도: O(노드 개수)
+// 공간 복잡도: O(1)