46 lines
857 B
Java
46 lines
857 B
Java
import java.util.*;
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public class Quicksort {
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static Random rnd = new Random();
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public static void quickSort(int[] a, int low, int high) {
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if (low >= high)
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return;
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int separator = a[low + rnd.nextInt(high - low + 1)];
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int i = low;
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int j = high;
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while (i <= j) {
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while (a[i] < separator)
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++i;
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while (a[j] > separator)
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--j;
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if (i <= j) {
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int t = a[i];
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a[i] = a[j];
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a[j] = t;
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++i;
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--j;
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}
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}
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quickSort(a, low, j);
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quickSort(a, i, high);
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}
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// test
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public static void main(String[] args) {
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int n = 10_000_000;
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int[] a1 = rnd.ints(n).toArray();
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int[] a2 = a1.clone();
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Arrays.sort(a2);
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long time = System.currentTimeMillis();
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quickSort(a1, 0, a1.length - 1);
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System.out.println(System.currentTimeMillis() - time);
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if (!Arrays.equals(a1, a2))
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throw new RuntimeException();
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}
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}
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