public class MergeSort {
static int number=0;
public static void main(String[] args) {
int[] a = {26, 5, 98, 108, 28, 99, 100, 56, 34, 1 };
printArray("排序前：",a);
MergeSort(a);
printArray("排序后：",a);
}
private static void printArray(String pre,int[] a) {
System.out.print(pre+"\n");
for(int i=0;i
System.out.print(a[i]+"\t");
System.out.println();
}
private static void MergeSort(int[] a) {
// TODO Auto-generated method stub
System.out.println("开始排序");
Sort(a, 0, a.length - 1);
}
private static void Sort(int[] a, int left, int right) {
if(left>=right)
return;
int mid = (left + right) / 2;
//二路归并排序里面有两个Sort，多路归并排序里面写多个Sort就可以了
Sort(a, left, mid);
Sort(a, mid + 1, right);
merge(a, left, mid, right);
}
private static void merge(int[] a, int left, int mid, int right) {
int[] tmp = new int[a.length];
int r1 = mid + 1;
int tIndex = left;
int cIndex=left;
// 逐个归并
while(left <=mid && r1 <= right) {
if (a[left] <= a[r1])
tmp[tIndex++] = a[left++];
else
tmp[tIndex++] = a[r1++];
}
// 将左边剩余的归并
while (left <=mid) {
tmp[tIndex++] = a[left++];
}
// 将右边剩余的归并
while ( r1 <= right ) {
tmp[tIndex++] = a[r1++];
}
System.out.println("第"+(++number)+"趟排序:\t");
// TODO Auto-generated method stub
//从临时数组拷贝到原数组
while(cIndex<=right){
a[cIndex]=tmp[cIndex];
//输出中间归并排序结果
System.out.print(a[cIndex]+"\t");
cIndex++;
}
System.out.println();
}
}
)
