203 solved. (#52)

Author: zwfang

README.md

@@ -65,6 +65,7 @@ continually updating 😃.
 * [83. Remove Duplicates from Sorted List](src/0083_remove_duplicates_from_sorted_list/rdfsl.go)
 * [86. Partition List](src/0086_partition_list/partition_list.go)   *`two pointers`*
 * [92. Reverse Linked List II](src/0092_reverse_linked_list_2/reverse_linked_list2.go)
+* [203. Remove Linked List Elements](src/0203_remove_linked_list_elements/remove_linked_list_elements.go)
 
 ### Dynamic Programming
 * [62. Unique Paths](./src/0062_unique_paths/unique_paths.go)   *`array`*

src/0203_remove_linked_list_elements/remove_linked_list_elements.go

@@ -0,0 +1,33 @@
+/*
+203. Remove Linked List Elements
+https://leetcode.com/problems/remove-linked-list-elements/
+
+Remove all elements from a linked list of integers that have value val.
+*/
+// time: 2019-01-07
+
+package rlle
+
+// ListNode Definition for singly-linked list.
+type ListNode struct {
+	Val  int
+	Next *ListNode
+}
+
+// time complexity: O(n)
+// space complexity: O(1)
+func removeElements(head *ListNode, val int) *ListNode {
+	dummyHead := &ListNode{}
+	dummyHead.Next = head
+
+	cur := dummyHead
+
+	for cur.Next != nil {
+		if val == cur.Next.Val {
+			cur.Next = cur.Next.Next
+		} else {
+			cur = cur.Next
+		}
+	}
+	return dummyHead.Next
+}

src/0203_remove_linked_list_elements/remove_linked_list_elements_test.go

@@ -0,0 +1,27 @@
+package rlle
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestRemoveElements(t *testing.T) {
+	head := createSinglyLinkedList([]int{1, 2, 6, 3, 4, 5, 6})
+	val := 6
+	expected := createSinglyLinkedList([]int{1, 2, 3, 4, 5})
+
+	if res := removeElements(head, val); !reflect.DeepEqual(res, expected) {
+		t.Errorf("expected %v, got %v", expected, res)
+	}
+}
+
+func createSinglyLinkedList(nums []int) *ListNode {
+	head := &ListNode{}
+	cur := head
+
+	for _, num := range nums {
+		cur.Next = &ListNode{Val: num}
+		cur = cur.Next
+	}
+	return head.Next
+}

src/README.md

@@ -64,6 +64,7 @@
 |0167|[Two Sum II - Input array is sorted](./0167_two_sum2/two_sum2.go)|Easy|*`对撞指针(双索引)`*|
 |0198|[House Robber](./0198_house_robber/house_robber.go)|Easy|*`memory search;`* *`dynamic programming`*|
 |0200|[200. Number of Islands](0200_number_of_island/number_of_island.go)|Medium|*`dfs;`* *`bfs`*|
+|0203|[203. Remove Linked List Elements](0203_remove_linked_list_elements/remove_linked_list_elements.go)|Easy|*`linked list`*|
 |0209|[Minimum Size Subarray Sum](./0209_minimum_size_subarray_sum/minimum_size_subarray_sum.go)|Medium|*`sliding window`*|
 |0215|[215. Kth Largest Element in an Array](0215_kth_largest_element_in_an_array/kthleiaa.go)|Medium|*`sort`*|
 |0226|[Invert Binary Tree](./0226_invert_binary_tree/invert_binary_tree.go)|Easy|*`recursion; `* *`binary tree`*|