Leetcode刷题

Problem 89

Posted by Ruizhi Ma on October 27, 2020

Solution URL

https://leetcode.com/submissions/detail/413893729/

代码

class Solution {
    public List<Integer> grayCode(int n) {
        //ans:https://leetcode-cn.com/problems/gray-code/solution/gray-code-jing-xiang-fan-she-fa-by-jyd/
        List<Integer> gray = new ArrayList<>();
        gray.add(0);

        for(int i = 0; i < n; i++){
            int head = 1 << i;
            for(int j = gray.size() - 1; j >= 0; j--){
                //上半部分一样，不用动，只要添加下半部分就可以
                //下半部分就是上半部分逆序，前面加1
                gray.add(head + gray.get(j));
            }
        }

        return gray;
    }
}