1 public class Solution { 2     public void sortColors(int[] A) { 3         int len=A.length; 4         int beg=0; 5         int end=len-1; 6         int cur=0; 7         while(cur<=end){ 8           if(A[cur]==0) 9           {10               swap(A,cur,beg);11               beg++;12               cur++;13               14               15           }16           else if(A[cur]==1)17           {18               cur++;19               20           }21           else22           {23               swap(A,cur,end);24               end--;25               26              27           }28             29         30         }31     }32         public void swap(int[] A,int i,int j)33         {34             int temp=A[i];35             A[i]=A[j];36             A[j]=temp;37             38             39             40         }41        42         43         44     }