Leetcode 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]
class Solution {
public:
    void sortColors(vector<int>& nums) {
        int p0 = 0;
        int p1 = 0;
        int curr = 0;
        
        // scan 0
        for(p0 = curr; p0 < nums.size(); p0++) {
            if (nums[p0] == 0) {
                swap(nums[p0], nums[curr]);
                curr++;
            }
        }
        
        // scan 1
        for(p1 = curr; p1 < nums.size(); p1++) {
            if (nums[p1] == 1) {
                swap(nums[p1], nums[curr]);
                curr++;
            }
        }
    }
};

Runtime: 0 ms, faster than 100.00% of C++ online submissions for Sort Colors.

Memory Usage: 8.3 MB, less than 70.30% of C++ online submissions for Sort Colors.