转圈圈

需求：

1-100号人，围成一个圈，从1号报数，123、123...报数，报3出圈圈，缩小圈圈，问最后留下那个人是多少号？

people=[]
a = 1
# 初始化数组
while a <= 100:
    people.append(a)
    a += 1
index = 1
# 开始报数
while True:
    if people[-1] == people[0]:
        break
    if index == 4:
        index = 1
        continue
    if index == 3:
        # 出队列
        del people[0]
    else:
        # 出队列后又重新入队列
        people.append(people[0])
        del people[0]
    index += 1
print(people)

结果：

image.png

Java实现

    public static void main(String[] args) {
        List<Integer> list = new LinkedList<>();
        for (int i = 1; i <= 100; i++) {
            list.add(i);
        }
        int index = 1;
        while (true) {
            if (index == 4) {
                index = 1;
            }
            if (list.size() == 1) {
                break;
            }
            if (index == 3) {
                list.remove(0);
            } else {
                list.add(list.get(0));
                list.remove(0);
            }
            index++;
        }
        System.out.println(list);
    }

image.png