微众Java方向笔试编程题

import java.math.BigInteger; import java.util.Scanner; public class Main { public static void main(String[]args){
        Scanner in = new Scanner(System.in);
        BigInteger n = in.nextBigInteger();
        BigInteger i = BigInteger.valueOf(0);
        BigInteger one = BigInteger.valueOf(1); int []a = new int[200]; for(int p=0;p<200;p++){
            a[p] = 0;
        } int len = 1;
        Integer ans = (Integer) 1; while (n.compareTo(i)>0){
            len=fun(a,len); if(fun2(a,len)){
                ans++;
            }
            i = i.add(one);
        }
        System.out.print(ans);
    }  public static int fun(int []a,int len){  if(a[0] == 0){
            a[0] = 1;  return len;
        }  int flag = 1; int i; for(i=0;i<len;i++){ if(a[i] + flag == 2){
                flag = 1;
                a[i] = 0;
            }else {
                a[i] = 1;
                flag = 0; break;
            }
        } if(i == len){
            a[i] = 1;
            len ++;
        } return len;
    } public static boolean fun2(int []a,int len){ int low = 0; int high = len-1; while (low<=high && a[low] == a[high]){
                low ++;
                high--;
            } if(low > high){ return true;
            } return false;
     }
}