package
com.ytx.array;
/** 题目: sort-colors
*
* 描述: 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(两次遍历)
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(一次遍历)
algorithm using only constant space?
*
*
@author
yuantian xin
*
* 元素取有限值为0,1,2的数组,这三个数分别分别代表红色,白色和蓝色。现在我们需要设计一个算法只需要一次遍历
* 就可以把数组按0,1,2的顺序排好序。
*/
public
class
Sort_colors {
public
void sortColors(int[]
A) {
int
i = -1;
//0的指针
int
j = -1;
//1的指针
int
k = -1;
//2的指针
for(int
index
= 0; index
< A.length;
index++) {
if(A[index]
== 0) {
A[++k] = 2;
A[++j] = 1;
A[++i] = 0;
}
else
if(A[index]
== 1) {
A[++k] = 2;
A[++j] = 1;
}
else
if(A[index]
== 2) {
A[++k] = 2;
}
}
}
public
static
void main(String[]
args) {
int[]
data={0,1,1,0,2,0,1,1,0,2,1};
new
Sort_colors().sortColors(data);
for(int
i
= 0; i
< data.length;
i++) {
System.out.print(data[i]
+ " ");
}
}
}