0002归并排序

来源：互联网发布：阿里云软件编辑：程序博客网时间：2024/05/16 11:13

public class sort {
   int[] arr;
   public sort(int[] arr){
       this.arr = arr;
   }

   public int[] sortArr(){
       //
       return sortArr1(this.arr);
   }

   private int[] sortArr1(int[] arr){
       //如果数组的长度=1，直接返回这个数组
       if(arr.length ==1){
           return arr;
       }

       //如果数组长度>1 ，2分解然后对分解后的数组各自排序
       int fen = arr.length/2;
       int[] arrLeft = new int[fen];
       int[] arrRight = new int[arr.length-fen];
       int i=0;
       for(int a:arr){
           if(i<fen){
               arrLeft[i] = a;
           }else{
               arrRight[i-fen] = a;
           }
           i++;
       }
       int[] arrLeftOk = sortArr1(arrLeft);
       int[] arrRightOk = sortArr1(arrRight);


       //把两个已经排好序的数组合并
       int[] arrOk = new int[arrLeftOk.length+arrRightOk.length];
       int Llen=0;
       int Rlen = 0;

       while(true){

           if(Llen==(arrLeftOk.length)&&Rlen==(arrRightOk.length)){
               break;
           }

           if(Llen==arrLeftOk.length){
               arrOk[Llen+Rlen] = arrRightOk[Rlen];
               Rlen++;
               continue;
           }

           if(Rlen==arrRightOk.length){
               arrOk[Llen+Rlen] = arrLeftOk[Llen];
               Llen++;
               continue;
           }

           if(arrLeftOk[Llen] >= arrRightOk[Rlen]){
               arrOk[Llen+Rlen] = arrRightOk[Rlen];
               Rlen++;
           }else{
               arrOk[Llen+Rlen] = arrLeftOk[Llen];
               Llen++;
           }
       }


       return arrOk;
   }

   public static void main(String[] args) {
       //int[] c = {1,2,2,0,2,2,2,2,3,4,5,6,7,8,9,1};
       int[] c =new int[1000000];
       int i=0;
       while(true){
           if(i>=1000000) break;
           c[i]=1000000-i;
           i++;
       }

       sort s = new sort(c);
       int[] b = s.sortArr();
       for(int b1:b){
           System.out.println(b1+",");
       }
   }
}