75 颜色分类

https://leetcode.cn/leetbook/read/top-interview-questions-medium/xvg25c/

cost: 28m29s

class Solution {
public:
    void sortColors(vector<int>& nums) {
        for (int i = 0, j = nums.size() - 1, k = nums.size() - 1;
             i <= k && k <= j;) {
            if (nums[i] == 0) {
                i++;
                continue;
            }
            if (nums[i] == 2) {
                if (i != k) {
                    std::swap(nums[k], nums[j]);
                }
                std::swap(nums[i], nums[j]);
                j--;
                k--;
                continue;
            }
            if (nums[i] == 1) {
                std::swap(nums[i], nums[k]);
                k--;
            }
        }
    }
};