首页 > 代码库 > [Leetcode] Sort Colors
[Leetcode] Sort Colors
Given an array with n objects colored red, white or blue, sort them so that objects of the same color are adjacent, with the colors in the order red, white and blue.
Here, we will use the integers 0, 1, and 2 to represent the color red, white, and blue respectively.
Note:
You are not suppose to use the library‘s sort function for this problem.
click to show follow up.
Follow up:
A rather straight forward solution is a two-pass algorithm using counting sort.
First, iterate the array counting number of 0‘s, 1‘s, and 2‘s, then overwrite array with total number of 0‘s, then 1‘s and followed by 2‘s.
Could you come up with an one-pass algorithm using only constant space?
Solution 1:
1 public class Solution { 2 public void sortColors(int[] A) { 3 if(A.length<=1) 4 return; 5 int iRed=0,iBlue=A.length-1; 6 int i=0; 7 while(i<=iBlue){ 8 if(A[i]==0){ 9 int temp=A[iRed];10 A[iRed]=A[i];11 A[i]=temp;12 iRed++;13 i++; //cannot be less than iRed 14 }else if(A[i]==2){15 int temp=A[iBlue];16 A[iBlue]=A[i];17 A[i]=temp;18 iBlue--;19 }else{20 i++;21 }22 }23 }24 }
Solution 2:
1 public class Solution { 2 public void sortColors(int[] A) { 3 int i=-1; //pointer for 0s 4 int j=-1; //pointer for 1s 5 int k=-1; //pointer for 2s 6 for(int m=0;m<A.length;++m){ 7 if(A[m]==0){ 8 A[++k]=2; 9 A[++j]=1;10 A[++i]=0;11 }else if(A[m]==1){12 A[++k]=2;13 A[++j]=1;14 }else{15 A[++k]=2;16 }17 }18 }19 }
i,j,k三个指针分别指向0,1,2段的结尾处。
[Leetcode] Sort Colors
声明：以上内容来自用户投稿及互联网公开渠道收集整理发布，本网站不拥有所有权，未作人工编辑处理，也不承担相关法律责任，若内容有误或涉及侵权可进行投诉： 投诉/举报 工作人员会在5个工作日内联系你，一经查实，本站将立刻删除涉嫌侵权内容。