237 solved. (#57)

Author: zwfang

README.md

@@ -69,6 +69,7 @@ continually updating 😃.
 * [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)
 * [206. Reverse Linked List](src/0206_reverse_linked_list/reverse_linked_list.go)
+* [237. Delete Node in a Linked List](src/0237_delete_node_in_a_linked_list/dniall.go)
 
 ### Dynamic Programming
 * [62. Unique Paths](./src/0062_unique_paths/unique_paths.go)   *`array`*

src/0237_delete_node_in_a_linked_list/dniall.go

@@ -0,0 +1,31 @@
+/*
+237. Delete Node in a Linked List
+https://leetcode.com/problems/delete-node-in-a-linked-list/
+
+Write a function to delete a node (except the tail) in a singly linked list, given only access to that node.
+
+Note:
+The linked list will have at least two elements.
+All of the nodes' values will be unique.
+The given node will not be the tail and it will always be a valid node of the linked list.
+Do not return anything from your function.
+*/
+// time: 2019-01-07
+
+package dniall
+
+// ListNode Definition for singly-linked list.
+type ListNode struct {
+	Val  int
+	Next *ListNode
+}
+
+// time complexity: O(1)
+// space complexity: O(1)
+func deleteNode(node *ListNode) {
+	// The linked list will have at least two elements.
+	// All of the nodes' values will be unique.
+	// The given node will not be the tail and it will always be a valid node of the linked list.
+	node.Val = node.Next.Val
+	node.Next = node.Next.Next
+}

src/0237_delete_node_in_a_linked_list/dniall_test.go

@@ -0,0 +1,26 @@
+package dniall
+
+import (
+	"reflect"
+	"testing"
+)
+
+func createSinglyLinkedList(nums []int) *ListNode {
+	head := &ListNode{}
+	cur := head
+
+	for _, num := range nums {
+		cur.Next = &ListNode{Val: num}
+		cur = cur.Next
+	}
+	return head.Next
+}
+
+func TestDeleteNode(t *testing.T) {
+	root := createSinglyLinkedList([]int{4, 5, 1, 9})
+	node := root.Next
+	expected := createSinglyLinkedList([]int{4, 1, 9})
+	if deleteNode(node); !reflect.DeepEqual(expected, root) {
+		t.Errorf("expected %v, got %v", expected, root)
+	}
+}

src/README.md

@@ -72,6 +72,7 @@
 |0219|[219. Contains Duplicate II](0219_contains_duplicate_2/contains_duplicate_2.go)|Easy|*`map`*|
 |0226|[Invert Binary Tree](./0226_invert_binary_tree/invert_binary_tree.go)|Easy|*`recursion; `* *`binary tree`*|
 |0235|[235. Lowest Common Ancestor of a Binary Search Tree](0235_lowest_common_ancestor_of_a_binary_search_tree/lcaoabst.go)|Easy|*`recursion; `* *`binary tree`*|
+|0237|[237. Delete Node in a Linked List](0237_delete_node_in_a_linked_list/dniall.go)|Easy|*`linked list`*|
 |0283|[Move Zeroes(solution1)](./0283_move_zeroes/move_zeroes.go) <br/>  [Move Zeroes(solution2)](./0283_move_zeroes/move_zeroes2.go)|Easy|*`array`*|
 |0300|[Longest Increasing Subsequence](./0300_longest_increasing_subsequence/lis.go)|Medium|*`dp`*|
 |0303|[303. Range Sum Query - Immutable](0303_range_sum_query/rsqim.go)|Easy||