快速排序算法（Java）

快速排序的理念主要是使用分治

public class Quick {
    public static void sort(Comparable[] a){
        int lo = 0;
        int hi = a.length-1;
        sort(a,lo,hi);

    }
    private static void sort(Comparable[] a,int lo,int hi){
        if(hi<=lo){
            return;
        }
        // 对a数组中，从lo到hi的元素进行切分
        int partition = partition(a,lo,hi);
        // 对左边分组中的元素进行排序
        sort(a,lo,partition-1);
        // 对右边分组中的元素进行排序
        sort(a,partition+1,hi);
    }

    public static int partition(Comparable[] a, int lo, int hi){
        Comparable key = a[lo];
        int left = lo;
        int right = hi+1;

        while(true){
            while(less(key,a[--right])){
                if(right == lo){
                    break;
                }
            }

            while (less(a[++left],key)){
                if(left == hi){
                    break;
                }
            }
            if(left >= right){
                break;
            }else{
                exch(a,left,right);
            }
        }
        exch(a,lo,right);
        return right;
    }

    private static void exch(Comparable[] a,int i,int j){
        Comparable t = a[i];
        a[i] = a[j];
        a[j] = t;
    }
    private static boolean less(Comparable v,Comparable w){
        return v.compareTo(w)<0;
    }
}