feat: 86_partition_list

86_partition_list/main.cpp

@@ -0,0 +1,43 @@
+struct ListNode {
+    int val;
+    ListNode* next;
+    ListNode() : val(0), next(nullptr) {}
+    ListNode(int x) : val(x), next(nullptr) {}
+    ListNode(int x, ListNode* next) : val(x), next(next) {}
+};
+
+class Solution {
+   public:
+    ListNode* partition(ListNode* head, int x) {
+        ListNode* current_node = head;
+        ListNode* insert_node = nullptr;
+        ListNode* last_node = nullptr;
+
+        while (current_node) {
+            if (current_node->val < x) {
+                ListNode* tmp_node = current_node;
+
+                if (last_node) {
+                    last_node->next = tmp_node->next;
+                } else {
+                    head = head->next;
+                }
+
+                if (insert_node) {
+                    tmp_node->next = insert_node->next;
+                    insert_node->next = tmp_node;
+                    insert_node = tmp_node;
+                } else {
+                    tmp_node->next = head;
+                    head = tmp_node;
+                    insert_node = tmp_node;
+                }
+            }
+
+            last_node = current_node;
+            current_node = current_node->next;
+        }
+
+        return head;
+    }
+};