hello-algo/codes/csharp/chapter_searching/hashing_search.cs

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2022-12-23 15:42:02 +08:00
using hello_algo.include;
using NUnit.Framework;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace hello_algo.chapter_searching
{
public class hashing_search
{
/* 哈希查找(数组) */
static int hashingSearch(Dictionary<int, int> map, int target)
{
// 哈希表的 key: 目标元素value: 索引
// 若哈希表中无此 key ,返回 -1
return map.GetValueOrDefault(target, -1);
}
/* 哈希查找(链表) */
static ListNode? hashingSearch1(Dictionary<int, ListNode> map, int target)
{
// 哈希表的 key: 目标结点值value: 结点对象
// 若哈希表中无此 key ,返回 null
return map.GetValueOrDefault(target);
}
[Test]
public void Test()
{
int target = 3;
/* 哈希查找(数组) */
int[] nums = { 1, 5, 3, 2, 4, 7, 5, 9, 10, 8 };
// 初始化哈希表
Dictionary<int, int> map = new();
for (int i = 0; i < nums.Length; i++)
{
map[nums[i]] = i; // key: 元素value: 索引
}
int index = hashingSearch(map, target);
Console.WriteLine("目标元素 3 的索引 = " + index);
/* 哈希查找(链表) */
ListNode head = ListNode.ArrToLinkedList(nums);
// 初始化哈希表
Dictionary<int, ListNode> map1 = new();
while (head != null)
{
map1[head.val] = head; // key: 结点值value: 结点
head = head.next;
}
ListNode? node = hashingSearch1(map1, target);
Console.WriteLine("目标结点值 3 的对应结点对象为 " + node);
}
}
}