[英]How to store hash codes of a String Array list in an array list
我需要幫助,將字符串數組列表“ randomNumbersStrg”的哈希碼存儲在另一個數組列表中。 我的老師希望我們生成100萬個隨機整數,將其轉換為字符串,然后獲取每個字符串的哈希碼。 有人可以幫助我生成哈希碼並將其存儲到鏈接列表中嗎? 這是我到目前為止所擁有的:
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;
}
}
只需使用一個LinkedList
存儲哈希碼,並使用ArrayList
存儲搜索時間:
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());
}
這將用於哈希碼。
然后遍歷hashCodes
列表以搜索每個元素,計算所需的時間:
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);
}
這應該做。 然后,您可以使用durations
列表來計算平均值和標准差。 祝好運!
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