Code:
public class QuickSort {
public static void main(String...args) {
int[] a = { 2, 5, 7, 3, 5, 9, 0};
QuickSort qs = new QuickSort();
qs.sort(a);
for(int i = 0; i < a.length; i++) {
System.out.println(a[i]);
}
}
public void sort(int[] a) {
sort(a, 0, a.length - 1);
}
private void sort(int[] a, int lo, int hi) {
if(lo >= hi) return;
int mid = partition(a, lo, hi);
sort(a, lo, mid - 1);
sort(a, mid + 1, hi);
}
private int partition(int[] a, int lo, int hi) {
int v = a[lo];
int i = lo;
int j = hi + 1;
while(true) {
while(a[++i] <= v) if(i == hi) break;
while(a[--j] >= v) if(j == lo) break;
if(i >= j) break;
exch(a, i, j);
}
exch(a, lo, j);
return j;
}
private void exch(int[] a, int i, int j) {
int tmp = a[i];
a[i] = a[j];
a[j] = tmp;
}
}
