思路：这题还是蛮有意思的，-2进制的转换，和2进制其实是差不多的，唯一注意的是如果除-2得出来的余数是负数的话要把它转为正数，同时商+1即可了
#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
const int maxn = 100000+7;
char ans[maxn];
int main()
{
int n,p=0;
scanf("%d",&n);
if(n==0)
{
printf("0\n");
return 0;
}
while(n)
{
int y = n%(-2); //余数
int s = n/(-2); //商
if(y<0)
{
y+=2;
s++;
}
n=s;
ans[++p]=y;
}
for(int i = p;i>=1;i--)printf("%d",ans[i]);
printf("\n");
}
Inexperienced in the digital arts, the cows tried to build a calculating engine (yes, it's a cowmpouter) using binary numbers (base 2) but instead built one based on base negative 2! They were quite pleased since numbers expressed in base −2 do not have a sign bit.
You know number bases have place values that start at 1 (base to the 0 power) and proceed right-to-left to base^1, base^2, and so on. In base −2, the place values are 1, −2, 4, −8, 16, −32, ... (reading from right to left). Thus, counting from 1 goes like this: 1, 110, 111, 100, 101, 11010, 11011, 11000, 11001, and so on.
Eerily, negative numbers are also represented with 1's and 0's but no sign. Consider counting from −1 downward: 11, 10, 1101, 1100, 1111, and so on.
Please help the cows convert ordinary decimal integers (range -2,000,000,000..2,000,000,000) to their counterpart representation in base −2.
Input
Line 1: A single integer to be converted to base −2
Output
Line 1: A single integer with no leading zeroes that is the input integer converted to base −2. The value 0 is expressed as 0, with exactly one 0.
Sample Input
-13
Sample Output
110111
Hint
Explanation of the sample:
Reading from right-to-left:
1*1 + 1*-2 + 1*4 + 0*-8 +1*16 + 1*-32 = -13
