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.
Here, we will use the integers 0, 1, and 2 to represent the color red, white, and blue respectively.
Follow up:
Could you solve this problem without using the library's sort function? Could you come up with a one-pass algorithm using only O(1) constant space?
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] Example 3:
Input: nums = [0] Output: [0] Example 4:
Input: nums = [1] Output: [1]
Constraints:
n == nums.length 1 <= n <= 300 nums[i] is 0, 1, or 2.
public class Solution {
public void SortColors(int[] nums) {
int left = 0;
int right = nums.Length-1;
for(int i=0;i<=right;i++){
while(nums[i]==2 && i<right){
swap(ref nums[i], ref nums[right]);
right--;
}
while(nums[i]==0 && i>left){
swap(ref nums[i], ref nums[left]);
left++;
}
}
}
private void swap(ref int a, ref int b){
int temp = a;
a = b;
b = temp;
}
}Time Complexity: O(n)
Space Complexity: O(1)
