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]
Constraints:
- n == nums.length
- 1 <= n <= 300
- nums[i] is either 0, 1, or 2.
Follow up: Could you come up with a one-pass algorithm using only constant extra space?
class Solution {
public void sortColors(int[] nums) {
int len = nums.length;
if(len < 2){
return;
}
int left = 0;
int right = len - 1;
int current = 0;
while(current <= right) {
if(nums[current] == 0){
swap(nums, left, current);
left++;
current++;
}else if(nums[current] == 1) {
current++;
}else {
swap(nums, right, current);
right--;
}
}
}
private void swap(int[] nums, int i, int j){
int temp = nums[i];
nums[i] = nums[j];
nums[j] = temp;
}
}快速排序的思想