LeetCode(Sorting&Seraching)Sort Colors

Sort Colors

Given an array with n objects colored red, white or blue, sort them in-place 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.

Example:

Input: [2,0,2,1,1,0]
Output: [0,0,1,1,2,2]

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 a one-pass algorithm using only constant space?

思路：拿到题目以后第一感受：这不就是个排序吗？话不多说，正好练练前一段时间写过的插入排序，因为都是0,1,2的序列，基本有序，所以用插入排序效率应该比较高，果不其然，leetcode上击败了70%多的人。

代码如下：

class Solution {
    public void sortColors(int[] nums) {
        for(int i=0;i<nums.length;i++){
            int temp=nums[i];
            int j;
            for(j=i-1;j>=0 && temp<nums[j];j--){
                nums[j+1]=nums[j];
            }
            nums[j+1]=temp;
        }
    }
}