如何将字符串数组列表的哈希码存储在数组列表中

Question

我需要帮助将字符串数组列表“hashNumberStrg”的哈希码存储在另一个数组列表中。我的导师希望我们生成100万个随机整数，将它们转换为字符串，然后获取每个字符串的哈希码。有人可以帮助我生成哈希码并将它们存储到链接列表中吗？以下是我迄今为止：

import java.util.*; 

public class dataStuctures 
{ 

    public static void main(String[] args) 
    { 
    int MAXIMUM = 5;//initializing the maximum integer 
    int MINIMUM = 1;//initializing the minimum integer 

    Random randomGenerator = new Random();//initializing the generation of random integers 

    int range = MAXIMUM - MINIMUM + 1;//setting the range of integers from 1 to 1,000,000 

    ArrayList<Integer> randomNumbers = new ArrayList<Integer>(5);//initializing an ArrayList to store the generated random integers with the capacity of 1,000,000 

    //ArrayList<String> randomNumbersStrg = new ArrayList<String>();//initializing an ArrayList to store store the generated hashcodes into a string 

    for (int index = 1; index <= 5; ++index)//for loop to generate 1,000,000 random integers in a range from 1 to 1,000,000 
    { 
      int randomInt = randomGenerator.nextInt(range) + MINIMUM; 

      randomNumbers.add(randomInt);//storing randomly generated numbers in a vector 


    }//end of for loop for random number generation and storage in an ArrayList 

    System.out.println("random numbers= " + randomNumbers); 
    System.out.println("ArrayList size: " + randomNumbers.size()); 



    ArrayList<String> randomNumbersStrg = new ArrayList<String>(randomNumbers.size()); 
    ArrayList<String> randomNumbersHashCodes = new ArrayList<String>(randomNumbers.size()); 
    for (Integer myInt : randomNumbers) 
    { 
     randomNumbersStrg.add(String.valueOf(myInt)); 
     randomNumbersHashCodes.add(randomNumbersStrg.get(myInt)); 
    } 




    // to test to make sure the integers converted 
    String first = randomNumbersStrg.get(0); 
    System.out.println("hash codeest = " + first.hashCode()); 
    String second = randomNumbersStrg.get(1); 
    String third = randomNumbersStrg.get(2); 
    String fourth = randomNumbersStrg.get(3); 
    String fifth = randomNumbersStrg.get(4); 
    System.out.println("\nfirst = " + first); 
    System.out.println("second = " + second); 
    System.out.println("third = " + third); 
    System.out.println("fourth = " + fourth); 
    System.out.println("fifth = " + fifth); 


    List<String> linkedList = new LinkedList<String>();//initializing Linked List 
    linkedList.addAll(randomNumbersStrg);//adding generated hashcodes to Linked List 







    }//end of main method 

    private static long[] randomNumbers(int index2) 
    { 
    // TODO Auto-generated method stub 
    return null; 
    } 
} 

Answer 1

只需使用一个LinkedList存储哈希码和ArrayList存储搜索次数：

List<Integer> hashCodes = new LinkedList<>(); 
for (int index = 0; index < 1_000_000; ++index) { 
    int randomInt = randomGenerator.nextInt(range) + MINIMUM; 
    hashCodes.add(String.valueOf(randomInt).hashCode()); 
} 

这将做它的散列码。

然后遍历hashCodes列表来搜索每一个元素，计算需要多长时间：

List<Long> durations = new ArrayList<>(hashCodes.size()); 
for (int n : hashCodes) { 
    long start = System.nanoTime(); 
    hashCodes.contains(n); // true 
    long end = System.nanoTime(); 
    durations.add(end - start); 
} 

这应该这样做。然后你有durations列表来计算average和std dev。祝你好运！