Quick Sort (Java version)

(This point is the main sorting method is applied recursively) 

Package sorting; 

Import java.util.Arrays; 

/ ** 
* Quicksort 
* / 
public class the demo1 { 
    public static void main (String [] args) { 
        int A [] = { . 1,. 8, 2,. 4,. 3,. 9,. 5,. 6}; 
        Go (A, 0, a.length -. 1); 
        System.out.println (of Arrays.toString (A)); 
    } 

    / ** 
     * for sorting, find the cut-off value, and based on the boundary, the left and right parts sequencing continues 
     * / 
    public static void Go (int [] A, int left, int right) { 
        IF (left <right) { 
            int qsort MID = (A , left, right); 
            Go (a, 0, MID -. 1); 
            ; Go (a, + MID. 1, right) 
        } 
    } 

    / ** 
     embodied sort --- * ---
     * 1, is first left index value as a comparison element, sequentially from the right array moving forward, until the value is greater than the value of the right to the left, out of a while loop 
     * 2, perform switching method, the second loop 
     * 3, or to the left as a reference index, but the index cycle is advanced from the back left, to the right until the value greater than the value of the left side, second bounce while loop 
     * 4, perform switching method, a second round of cycle 
     * 5, when the left end of the whole cycle, after the value of the return left right> is the cut-off value 
     * / 
    public static int qsort (int [] a, int left, int right) { 
        the while (left <right) { 
            the while (left <right A && [left] <= A [right]) { 
                right -; 
            } 
            IF (left <right) { 
                the swap (A, left, right); 
            } 
            the while (left <right && A [left] <= A [right ]) { 
                left ++; 
            } 
            IF (left <right) {
                swap(a, left, right);
            }
        }
        return left;
    }

    /**
     * 交换
     */
    public static void swap(int[] a, int left, int right) {
        int temp = a[left];
        a[left] = a[right];
        a[right] = temp;
    }
}