items10000個のソートされたランダムint値を持つ配列でシーケンシャル検索とバイナリ検索を実行するプログラムを作成しようとしています。呼び出された 2 番目の配列には、1000 個の値 (配列からの500 個の値と、配列にない 500個の値)targetsがロードされます。intitemsitems
int基本的に、検索では配列内の値を探すために項目配列を通過する必要がありますtargets。これは私のコードです:
import java.util.*;
// Loads two arrays with integers
// Searches the arrays using sequential search and binary search
// Compares the time for each search
public class Searches {
private int items[], targets[];
public Searches() {
this.items = new int[10000];
this.targets = new int[1000];
}
public void loadItemsAndTargets(){
int nextValue = 100;
int index = 0;
Random generator = new Random(1);
items[0] = nextValue;
/* load the items array with items to be searched through */
for (index = 1; index < items.length; index++){
nextValue = nextValue + generator.nextInt(100);
items[index]= nextValue;
}
/* load the targets array with target values that will be searched for within
* array items, and target values that are not within array items
*/
index = 0;
while (index < targets.length){
targets[index] = items[index*10];
targets[index+1] = generator.nextInt(100);
index = index + 2;
}
}
public int sequentialSearch(int target) {
/* Using the sequential search algorithm, search the items array for the target value passed
* If found, return the index in the items array, otherwise return -1
*/
this.loadItemsAndTargets();
int key = target;
int index;
boolean found = false;
index = 0;
while ((!found) && (index < items.length))
if (key == target)
found = true;
else
index = index + 1;
if (!found)
index = -1;
return index;
}
public int binarySearch(int target){
/* Using the binary search algorithm, search the items array for the target value passed
* If found, return the index in the items array, otherwise return -1
*/
this.loadItemsAndTargets();
target = targets.length;
int key = target;
boolean found = false;
int guess = 0;
int low = 0;
int high = items.length - 1;
while ((!found) && (low < high)) {
guess = (high+low)/2;
if (key == items[guess])
found = true;
else if (key < items[guess])
high = guess - 1;
else
low = guess + 1;
if (!found)
return - 1;
}
return guess;
}
public static void main(String[] args) {
int index = 0;
Searches searcher = new Searches();
searcher.loadItemsAndTargets();
/* call the method that searches array items
* for each of the values in array targets
* using the sequential search algorithm
* print the approximate elapsed time in milliseconds
* For the FIRST FIVE searches print out the index
* where target value was found or print -1 if it was not found
*/
long startTimeSequential;
startTimeSequential = System.currentTimeMillis();
System.out.println(searcher.sequentialSearch(index));
long endTimeSequential;
endTimeSequential = System.currentTimeMillis();
long totalTimeSequential;
totalTimeSequential = endTimeSequential-startTimeSequential;
System.out.println("sequential search time: " + totalTimeSequential + " milliseconds");
/* call the method that searches array items
* for each of the values in array targets
* using the binary search algorithm
* print the approximate elapsed time in milliseconds
* For the FIRST FIVE searches print out the index
* where target value was found or print -1 if it was not found
*/
long startTimeBinary;
startTimeBinary = System.currentTimeMillis();
System.out.println(searcher.binarySearch(index));
long endTimeBinary;
endTimeBinary = System.currentTimeMillis();
long totalTimeBinary;
totalTimeBinary = endTimeBinary - startTimeBinary;
System.out.println("binary search time: " + totalTimeBinary + " milliseconds");
}
}
編集：出力はこれでなければなりません>
395
986
-1
14
-1
シーケンシャル検索時間: 40 ミリ秒
395
986
-1
14
-1
バイナリ検索時間: 0 ミリ秒