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?
my code:
class Solution { public: void sortColors(vector<int>& nums) { int len = nums.size(); for (int i = 1; i <= len; ++i) { for (int j = i-1; j > 0; --j) { if (nums[j] < nums[j-1]) { int con = nums[j]; nums[j] = nums[j-1]; nums[j-1] = con; } } } } };
Runtime: 0 ms, faster than 100.00% of C++ online submissions for Sort Colors.