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solved s12 ex2

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navid.sassan 2020-12-14 15:45:58 +01:00
parent 1d862d57bc
commit d9414c81ed
1 changed files with 31 additions and 3 deletions
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34
12/src/main/java/ch/zhaw/ads/QuickerSortServer.java
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@ -1,24 +1,39 @@
package ch.zhaw.ads; package ch.zhaw.ads;
import java.util.Arrays;
import java.util.Random; import java.util.Random;
import java.util.function.Consumer;
public class QuickerSortServer implements CommandExecutor { public class QuickerSortServer implements CommandExecutor {
int QUICKSORT_THRESHOLD = 70;
@Override @Override
public String execute(String command) { public String execute(String command) {
StringBuffer result = new StringBuffer();
int[] testdata = new int[1000]; int[] testdata = new int[1000];
Random random = new Random(); Random random = new Random();
for (int i=0; i < testdata.length; i++) { for (int i=0; i < testdata.length; i++) {
testdata[i] = random.nextInt(1000000); testdata[i] = random.nextInt(1000000);
} }
quickSort(testdata);
return "Is sorted: " + checkSorted(testdata); double arraysSortRuntime = timeit(Arrays::sort, testdata);
result.append("Is sorted: " + checkSorted(testdata) + "\n");
result.append("quickSort runtime: " + arraysSortRuntime + "ms\n");
result.append("quickSort runtime:\n");
// for (int i = 0; i < 1000; i++)
for (int i = 40; i < 100; i++) {
QUICKSORT_THRESHOLD = i;
double quickSortRuntime = timeit(this::quickSort, testdata);
result.append(QUICKSORT_THRESHOLD + "," + quickSortRuntime + "\n");
}
return result.toString();
} }
private void quickSort(int[] a, int left, int right) { private void quickSort(int[] a, int left, int right) {
if (left < right) { if (left < right) {
int mid = partition (a, left, right); int mid = partition (a, left, right);
if (mid <= 50) { if (mid <= QUICKSORT_THRESHOLD) {
insertSort(a); insertSort(a);
} else { } else {
quickSort(a, left, mid-1); quickSort(a, left, mid-1);
@ -68,4 +83,17 @@ public class QuickerSortServer implements CommandExecutor {
a[i] = x; a[i] = x;
} }
} }
private double timeit(Consumer<int[]>func, int[] a) {
long end, start = System.currentTimeMillis();
int count = 0;
int[] testarray = new int[a.length];
do {
System.arraycopy(a, 0, testarray, 0, a.length);
func.accept(testarray);
count++;
end = System.currentTimeMillis();
} while (end - start < 1000);
return (double)(end-start)/count;
}
} }