Merge pull request #3 from codewithme-py/feat/remove-duplicates-from-sorted-list-0083

problem solution & test 0083

Author: codewithme-py

solutions/remove_duplicates_from_sorted_list_0083.py

@@ -0,0 +1,20 @@
+class ListNode:
+    def __init__(self, val: int = 0, next: 'ListNode | None' = None):
+        self.val = val
+        self.next = next
+
+
+class Solution:
+    def deleteDuplicates(self, head: ListNode | None) -> ListNode | None:
+        """Remove all duplicates from a sorted linked list
+        (keep only one occurrence).
+        """
+        if not head:
+            return None
+        curr = head
+        while curr.next:
+            if curr.val == curr.next.val:
+                curr.next = curr.next.next
+            else:
+                curr = curr.next
+        return head

tests/test_remove_duplicates_from_sorted_list_0083.py

@@ -0,0 +1,47 @@
+from solutions.remove_duplicates_from_sorted_list_0083 import ListNode, Solution
+
+
+def list_to_linked_list(arr):
+    if not arr:
+        return None
+    head = ListNode(arr[0])
+    curr = head
+    for val in arr[1:]:
+        curr.next = ListNode(val)
+        curr = curr.next
+    return head
+
+
+def linked_list_to_list(head):
+    res = []
+    curr = head
+    while curr:
+        res.append(curr.val)
+        curr = curr.next
+    return res
+
+
+def test_delete_duplicates():
+    sol = Solution()
+
+    head1 = list_to_linked_list([1, 1, 2])
+    result1 = sol.deleteDuplicates(head1)
+    assert linked_list_to_list(result1) == [1, 2]
+
+    head2 = list_to_linked_list([1, 1, 2, 3, 3])
+    result2 = sol.deleteDuplicates(head2)
+    assert linked_list_to_list(result2) == [1, 2, 3]
+
+    assert sol.deleteDuplicates(None) is None
+
+    head3 = ListNode(5)
+    result3 = sol.deleteDuplicates(head3)
+    assert linked_list_to_list(result3) == [5]
+
+    head4 = list_to_linked_list([7, 7, 7, 7])
+    result4 = sol.deleteDuplicates(head4)
+    assert linked_list_to_list(result4) == [7]
+
+    head5 = list_to_linked_list([1, 2, 3, 4])
+    result5 = sol.deleteDuplicates(head5)
+    assert linked_list_to_list(result5) == [1, 2, 3, 4]