s0203

include/s0203_remove_linked_list_elements.hpp

@@ -0,0 +1,17 @@
+#ifndef S0203_REMOVE_LINKED_LIST_ELEMENTS_HPP
+#define S0203_REMOVE_LINKED_LIST_ELEMENTS_HPP
+
+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 S0203 {
+ public:
+  ListNode* removeElements(ListNode* head, int val);
+};
+
+#endif

src/s0203_remove_linked_list_elements.cpp

@@ -0,0 +1,19 @@
+#include "s0203_remove_linked_list_elements.hpp"
+
+ListNode* S0203::removeElements(ListNode* head, int val) {
+  ListNode dummy = ListNode(0, head);
+  ListNode* ptr = &dummy;
+  while (ptr->next != nullptr) {
+    if (ptr->next->val == val) {
+      if (ptr->next->next == nullptr) {
+        ptr->next = nullptr;
+        break;
+      } else {
+        ptr->next = ptr->next->next;
+      }
+    } else {
+      ptr = ptr->next;
+    }
+  }
+  return dummy.next;
+}