83. Remove Duplicates from Sorted List

README.md

@@ -60,6 +60,7 @@ continually updating 😃.
 * [25. Reverse Nodes in k-Group](./src/0025_reverse_nodes_in_k_group/reverse_node_k_group.go)
 * [61. Rotate List](./src/0061_rotate_list/rotate_list.go)
 * [82. Remove Duplicates from Sorted List II](src/0082_remove_duplicates_from_sorted_list_2/rdfsl.go)
+* [83. Remove Duplicates from Sorted List](src/0083_remove_duplicates_from_sorted_list/rdfsl.go)
 
 ### Dynamic Programming
 * [62. Unique Paths](./src/0062_unique_paths/unique_paths.go)   *`array`*

src/0083_remove_duplicates_from_sorted_list/rdfsl.go

@@ -0,0 +1,38 @@
+/*
+83. Remove Duplicates from Sorted List
+https://leetcode.com/problems/remove-duplicates-from-sorted-list/
+
+Given a sorted linked list, delete all duplicates such that each element appear only once.
+*/
+
+package rdfsl
+
+// ListNode Definition for singly-linked list.
+type ListNode struct {
+	Val  int
+	Next *ListNode
+}
+
+// time complexity: O(n)
+// space complexity: O(1)
+func deleteDuplicates(head *ListNode) *ListNode {
+	if head == nil || head.Next == nil {
+		return head
+	}
+
+	var (
+		pre = head
+		cur = head.Next
+	)
+
+	for cur != nil {
+		if cur.Val == pre.Val {
+			pre.Next = cur.Next
+			cur = cur.Next
+		} else {
+			pre = cur
+			cur = cur.Next
+		}
+	}
+	return head
+}

src/0083_remove_duplicates_from_sorted_list/rdfsl_test.go

@@ -0,0 +1,35 @@
+package rdfsl
+
+import (
+	"reflect"
+	"testing"
+)
+
+func createSingleLinkedList(nums []int) *ListNode {
+	head := &ListNode{}
+	cur := head
+
+	for _, num := range nums {
+		cur.Next = &ListNode{Val: num}
+		cur = cur.Next
+	}
+	return head.Next
+}
+
+func TestDeleteDuplicates(t *testing.T) {
+	testCases := []*ListNode{
+		createSingleLinkedList([]int{1, 1, 2}),
+		createSingleLinkedList([]int{1, 1, 2, 3, 3}),
+		nil,
+	}
+	expected := []*ListNode{
+		createSingleLinkedList([]int{1, 2}),
+		createSingleLinkedList([]int{1, 2, 3}),
+		nil,
+	}
+	for index, head := range testCases {
+		if res := deleteDuplicates(head); !reflect.DeepEqual(res, expected[index]) {
+			t.Errorf("expected %v, got %v", expected[index], res)
+		}
+	}
+}

src/README.md

@@ -41,6 +41,7 @@
 |0079|[79. Word Search](0079_word_search/word_search.go)|Medium|*`backtracking;`**`array`*|
 |0080|[80. Remove Duplicates from Sorted Array II](0080_remove_duplicates_from_sorted_array2/rdfsa2.go)|Medium|*`double index`*|
 |0082|[82. Remove Duplicates from Sorted List II](0082_remove_duplicates_from_sorted_list_2/rdfsl.go)|Medium|*`linked list`*|
+|0083|[83. Remove Duplicates from Sorted List](0083_remove_duplicates_from_sorted_list/rdfsl.go)|Easy|*`linked list`*|
 |0088|[88. Merge Sorted Array](0088_merge_sorted_array/msa.go)|Easy|*`sort`*|
 |0094|[Binary Tree Inorder Traversal](./0094_binary_tree_inorder_traversal/binary_tree_inorder_traversal.go)|Medium|*`binary tree`*|
 |0100|[Same Tree](./0100_same_tree/same_tree.go)|Easy|*`binary tree`*|