归并排序

package www.com.sort;


public class MergeSort {


/*
* 归并排序，
* 算法将属猪分成两半，对每部分递归地应用归并排序，在两部分都排好序后，对它们进行归并
*/
    public static void mergeSort(int[] list){
    if(list.length>1){
    //merge sort the first half
    int[] firstHalf =new int[list.length/2];
    System.arraycopy(list, 0, firstHalf, 0, list.length/2);    
    mergeSort(firstHalf);
   
    //merge sort the second half
    int secondHalfLenfth=list.length-list.length/2;
    int[] secondHalf=new int[list.length-list.length/2];
    System.arraycopy(list, list.length/2, secondHalf, 0, secondHalfLenfth);
    mergeSort(secondHalf);
   
    //Merge firstHalf with secondHalf
    int[] temp =merge(firstHalf,secondHalf);
    System.arraycopy(temp, 0, list, 0, temp.length);    
         }
   }


    /*
     * merge two sorted list 
     * */
private static int[] merge(int[] list1, int[] list2) {
int[] temp= new int[list1.length+list2.length];
int current1=0;
int current2=0;
int current3=0;

while(current1<list1.length&&current2<list2.length){
if(list1[current1]<list2[current2]){
temp[current3++]=list1[current1++];
}else{
temp[current3++]=list2[current2++];
}
}

while(current1<list1.length){
temp[current3++]=list1[current1++];
}

while(current2<list2.length){
temp[current3++]=list2[current2++];
}
return temp;
}


public static void main(String[] args){
int[] list={1,3,2,5,4,6,8,7};
mergeSort(list);
for(int i=0,j=list.length;i<j;i++){
System.out.print(list[i]+" ");
}
}
}