Update and rename insertionSortList.cpp to insertion-sort-list.cpp

Author: kamyu104

C++/insertion-sort-list.cpp

@@ -0,0 +1,37 @@
+// Time:  O(n^2)
+// Space: O(1)
+
+/**
+ * Definition for singly-linked list.
+ * struct ListNode {
+ *     int val;
+ *     ListNode *next;
+ *     ListNode(int x) : val(x), next(NULL) {}
+ * };
+ */
+class Solution {
+    public:
+        ListNode *insertionSortList(ListNode *head) {
+        ListNode dummy{numeric_limits<int>::min()};
+
+        auto curr = head;
+        ListNode *position = nullptr;
+
+        while (curr) {
+            position = findInsertPosition(&dummy, curr->val);
+            ListNode *tmp = curr->next;
+            curr->next = position->next;
+            position->next = curr;
+            curr = tmp;
+        }
+
+        return dummy.next;
+    }
+
+    ListNode* findInsertPosition(ListNode *head, int x) {
+        ListNode *prev = nullptr;
+        for (auto curr = head; curr && curr->val <= x;
+             prev = curr, curr = curr->next);
+        return prev;
+    }
+};