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]
class Solution { public: void sortColors(vector<int>& nums) { int p1 = 0, p2 = 0, p3 = nums.size() - 1; while(p2 <= p3) { if (nums[p2] == 0) { swap(nums[p1], nums[p2]); ++p1; ++p2; } else if(nums[p2] == 2) { swap(nums[p2], nums[p3]); --p3; } else { ++p2; } } } };
原文：https://www.cnblogs.com/qiang-wei/p/12296493.html