有1到100共100个数, 从1开始, 每隔1, 2, 3... 个数拿走一个数, 最后剩下几?

 1     public static int selectNumber(int n) {
 2         
 3         int result = -1;
 4         ArrayList<Integer> nums = new ArrayList<Integer>();
 5         int index = 0;     // this variable is used to remove numbers from list 
 6         int count = 0;     // count is used to count which numbers should be remove
 7         int pIndex = 0;  // this is used to record previous index
 8         
 9         // generate a list contains numbers from 1 to n
10         for(int i = 1; i <= n; i++) {
11             nums.add(i);
12         }
13         
14         while(nums.size() > 1) {
15             
16             while(index < nums.size()) {
17                 nums.remove(index);     
18                 count++;
19                 pIndex = index;
20                 index += count;
21             }
22             
23             index = count - (nums.size() - pIndex);
24             
25             while(index > nums.size() - 1) {
26                 index = index - nums.size();
27             }
28         }
29         
30         result = nums.get(0);
31         return result;
32     }
33     
34     public static void main(String[] args) {
35         int surviver = selectNumber(100);
36         System.out.println("The surviver is: " + surviver);
37     }