Java之归并排序算法(一)

public class MergeSort {public static void mergeSort(int[] list) {if(list.length>1) {int[] firstHalf = new int[list.length/2];System.arraycopy(list, 0, firstHalf, 0, list.length/2);mergeSort(firstHalf);int secondHalfLength = list.length-list.length/2;int[] secondHalf = new int[secondHalfLength];System.arraycopy(list, list.length/2, secondHalf, 0, secondHalfLength);mergeSort(secondHalf);//merge firstHalf with secondHalfint[] temp = merge(firstHalf,secondHalf);System.arraycopy(temp, 0, list, 0, temp.length);}}private static int[] merge(int[] list1, int[] list2) {int[] temp = new int[list1.length+list2.length];int current1=0; // index in list1int current2=0; // index in list2int current3=0; // index in tempwhile(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) {// TODO 自动生成的方法存根int[] list = {2,3,2,5,6,1,-2,3,14,12};mergeSort(list);for( int i=0; i<list.length; i++ ) {System.out.print(list[i]+" ");}}}