uva 575 – Skew Binary

Skew Binary 

When a number is expressed in decimal, the k-th digit represents a multiple of 10k. (Digits are numbered from right to left, where the least significant digit is number 0.) For example,

 

When a number is expressed in binary, the k-th digit represents a multiple of 2k. For example,

 

In skew binary, the k-th digit represents a multiple of 2k+1 - 1. The only possible digits are 0 and 1, except that the least-significant nonzero digit can be a 2. For example,

 

The first 10 numbers in skew binary are 0, 1, 2, 10, 11, 12, 20, 100, 101, and 102. (Skew binary is useful in some applications because it is possible to add 1 with at most one carry. However, this has nothing to do with the current problem.)

Input 

The input file contains one or more lines, each of which contains an integer
n. If n = 0 it signals the end of the input, and otherwise n is a nonnegative integer in skew binary.

Output 

For each number, output the decimal equivalent. The decimal value of n will be at most 231 - 1 = 2147483647.

Sample Input 

1012020000000000000000000000000000010100000000000000000000000000000011100111110000011100001011011020000

Sample Output 

44214748364632147483647471041110737

由於long long 在vc上運行不了導致有個小錯誤沒發現，最後一個exp【31】忘了-1.wrong了十多次

#include <stdio.h>
#include <string.h>
int main()
{char s[100];
 long long i,l,exp[32],num;
 exp[1]=2;
 for (i=2;i<=31;i++)
 {exp[i]=2*exp[i-1];--exp[i-1];}
 --exp[31];
 while (gets(s))
 {
  l=strlen(s);
  if ((s[0]=='0')&&(l==1)) break;
  num=0;
  for (i=l-1;i>=0;i--)
  num+=(s[i]-'0')*exp[l-i];
  printf("%lld\n",num);
 }
 return 0;
}