https://leetcode.com/problems/elimination-game/// 一行代码就可以，不过原理有些复杂// https://discuss.leetcode.com/topic/58042/c-1-line-solution-with-explanation// return n == 1 ? 1 : 2 * (1 + n / 2 - lastRemaining(n / 2));// https://discuss.leetcode.com/topic/59293/easiest-solution-o-logn-with-explanationpublic class Solution {    public int lastRemaining(int n) {                boolean isLeft = true;        int left = n;        int step = 1;        int head = 1;                while (left != 1) {            if (isLeft || left % 2 == 1) {                head += step;            }            step *= 2;            left /= 2;            isLeft = !isLeft;        }        return head;            }}