75.Sort Colors
Given an array nums
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.
We will use the integers 0
, 1
, and 2
to represent the color red, white, and blue, respectively.
You must solve this problem without using the library’s sort function.
Example 1:
Input: nums = [2,0,2,1,1,0]
Output: [0,0,1,1,2,2]
Example 2:
Input: nums = [2,0,1]
Output: [0,1,2]
看到这个题我就想用冒泡排序法,但是一看答案有更简单的,是0就和前面换,是2就和后面换,但是要注意和后面换了之后要判断当前位置是几,因为后面的数据还没有判断,但是和前面换就不必了。
class Solution {
public void sortColors(int[] nums) {
int zero = 0, one = 0, two = nums.length-1;
while (one <= two){
if (nums[one] == 0) swap(nums, zero++, one++);
else if (nums[one] == 2) swap (nums,one,two--);
else one++;
}
}
private void swap (int[] nums, int i, int j){
int k = nums[i];
nums[i] = nums[j];
nums[j] =k;
}
}