2013
11-12

# The Moronic Cowmpouter

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.

Line 1: A single integer to be converted to base −2

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.

-13

110111

Explanation of the sample:

1*1 + 1*-2 + 1*4 + 0*-8 +1*16 + 1*-32 = -13

/* @author: */
import java.util.Scanner;
public class Main {

public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int i, n, h;
boolean s[]=new boolean[100];
n=sc.nextInt();
if( n == 0 ) {
System.out.printf( "0\n" );
return ;
}

i = 0;
h = 1;
while( n!=0 ) {
if( (n & 1)!=0 ) {
s[i] = true;
n -= h;
}
else
s[i] = false;
h = -h;
n >>= 1;
i++;
}

while(( i-- )!=0)
System.out.printf( "%d", s[i]?1:0 );

System.out.println();
}
}

1. #include <cstdio>
#include <cstring>

const int MAXSIZE=256;
//char store[MAXSIZE];
char str1[MAXSIZE];
/*
void init(char *store) {
int i;
store['A']=’V', store['B']=’W',store['C']=’X',store['D']=’Y',store['E']=’Z';
for(i=’F';i<=’Z';++i) store =i-5;
}
*/
int main() {
//freopen("input.txt","r",stdin);
//init(store);
char *p;
while(fgets(str1,MAXSIZE,stdin) && strcmp(str1,"STARTn")==0) {
if(p=fgets(str1,MAXSIZE,stdin)) {
for(;*p;++p) {
//*p=store[*p]
if(*p<’A’ || *p>’Z') continue;
if(*p>’E') *p=*p-5;
else *p=*p+21;
}
printf("%s",str1);
}
fgets(str1,MAXSIZE,stdin);
}
return 0;
}

2. 我没看懂题目
2
5 6 -1 5 4 -7
7 0 6 -1 1 -6 7 -5
我觉得第一个应该是5 6 -1 5 4 输出是19 5 4
第二个是7 0 6 -1 1 -6 7输出是14 7 7
不知道题目例子是怎么得出来的