I wrote the algorithm of the Basic Information Technology Engineer Examination as a practice in my own way.
A class made so that it can be used for practice such as the binary search method.
MessagePrinter.java
/**
*A class that prints a message of search results
*
* @author hatena
*
*/
import java.util.List;
public class MessagePrinter {
public void printFoundMessages(int targetNumber, List<Integer> targetList) {
System.out.println("Number of objects to search in the list" + targetNumber + "Existed.");
System.out.println("The search target list is" + targetList + "was.");
System.out.println("The index of the number of search targets is" + targetList.indexOf(targetNumber) + "is.");
}
public void printNotFoundMessages(int targetNumber, List<Integer> targetList) {
System.out.println("Number of objects to search in the list" + targetNumber + "Did not exist.");
System.out.println("The list to be searched is" + targetList + "was.");
}
}
The java.util.Random class had an ints () method that returned a specified range of IntStream.
I feel that the random numbers are biased. .. ..
RandomListCreator.java
import java.util.List;
import java.util.Random;
import java.util.stream.Collectors;
import lombok.AllArgsConstructor;
/**
*A class that creates a list of random positive integers.
*
* @author hatena
*
*/
@AllArgsConstructor
public class RandomListCreator {
public int lengthOfList;
public int maximumNumber;//ex:If you specify 50, the list generated will include 50.
/**
*A method that returns an unsorted list of integers of a specified length.
*
*
*/
public List<Integer> createRandUnorderdList() {
//Random number generation class
Random rand = new Random();
//@formatter:off
List<Integer> unorderdRandlist =
rand
.ints(this.lengthOfList, 0, this.maximumNumber + 1)
.boxed()
.collect(Collectors.toList());
//@formatter:on
return unorderdRandlist;
}
}
Simply look for matching numbers from the beginning.
SeqSearch.java
import java.util.List;
import lombok.AllArgsConstructor;
import lombok.Data;
/**
*A class that performs a linear search method (because it is an extended for statement, there is no sentinel turn.)
*
* @author hatena
*/
@Data
@AllArgsConstructor
public class SeqSearch {
private List<Integer> targetList;
/**
*Method of the linear search method body. Search in order from the beginning.
*
* @return Matched index. If they don't match-1 is returned.
*
*/
public int findTargetNum(int targetNumber) {
//Check if they match in order from the top of the list.
for (int num : this.targetList) {
//If the target number is included in the list, return the index number.
if (num == targetNumber) {
return this.targetList.indexOf(targetNumber);
}
}
//If they do not match to the end.
return -1;
}
}
MainSeq.java
import java.util.List;
import java.util.Scanner;
import common.MessagePrinter;
import common.RandomListCreator;
import seqsearch.SeqSearch;
/**
*Binary search method execution main class
*
* @author hatena
*
*/
public class MainSeq {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
//Have the user enter the information (length, maximum number in the list) needed to create a random list
System.out.print("Enter the length of the list as a positive integer:");
int lengthOfList = scanner.nextInt();
System.out.print("Enter the maximum number to include in the list:");
int maximumNumber = scanner.nextInt();
//Create a random list
RandomListCreator listCreator = new RandomListCreator(lengthOfList, maximumNumber);
List<Integer> targetList = listCreator.createRandUnorderdList();
System.out.println("I created a list of random numbers.");
//Enter the number you want to search as standard
System.out.print("Enter the number you want to linearly search:");
int targetNumber = scanner.nextInt();
System.out.println("In this list" + targetNumber + "Linear search for any.");
//Pass the list and the search target to the class of the linear search body.
SeqSearch seqSearch = new SeqSearch(targetList);
//Class instantiation for displaying result messages
MessagePrinter messagePrinter = new MessagePrinter();
//If it matches the list, an integer greater than or equal to 0 is returned and the result is printed.
if (seqSearch.findTargetNum(targetNumber) >= 0) {
messagePrinter.printFoundMessages(targetNumber, seqSearch.getTargetList());
} else {
messagePrinter.printNotFoundMessages(targetNumber, seqSearch.getTargetList());
}
scanner.close();
}
}
■ When the target number exists in the list
Enter the length of the list as a positive integer: 10
Enter the maximum number to include in the list: 15
I created a list of random numbers.
Enter the number you want to linearly search:9
Linear search for 9s in this list.
There were 9 search targets in the list.
The search target list is[0, 14, 14, 9, 6, 0, 4, 7, 15, 7]was.
The index of the number of objects to be searched is 3.
■ When the target number does not exist in the list
Enter the length of the list as a positive integer: 10
Enter the maximum number to include in the list: 15
I created a list of random numbers.
Enter the number you want to perform a linear search.:9
Linear search for 9s in this list.
The number 9 to be searched was not found in the list.
The list to be searched is[11, 7, 10, 10, 14, 4, 11, 3, 11, 1]was.
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