51Nod 1499 binary conversion problem.

Test instructions

Now there are a lot of weights, their weight is w0,w1,w2,... Each one of them. Ask if these weights can be used to represent something with a weight of M.

Analysis:

The topic was divided into greedy algorithm, but I did not think of greedy solution.

This is the question I think, if a number m is only used w,w^1 ... to say, that this number m into the W system is certainly only the number 0 and 1, but now we require that the number n is required two different m subtraction obtained, Also the same one of these two m cannot appear at the same time 1. Now is the request to give a n can be two such a different m subtract to get.

We can use the W-binary numbers of N to make a step-by-step judgment, using whether or not to be borrow. See the code specifically.

#include <iostream> #include <cstdio> #include <cstring> #include <cmath> #include <

Algorithm> using namespace std;
    int main () {Long long w,m;
    int a[100];
    int Num,ans,flag;
        while (scanf ("%lld%lld", &w,&m) ==2) {memset (a,0,sizeof (a));
        num = 0;
            while (m) {a[num++]=m%w;
        M/=w;
}//for (int i = num-1; I >= 0; i--)//{//cout<<a[i]<< "";
        }//cout<<endl;
        cout<<w<<endl;
        Ans = 0;
        Flag = 0; for (int i = 0; i < num; i++) {if (ans==0)//not borrow {//cout<<a
                [i]<<endl; if (a[i]==0| |
                A[i]==1) {ans = 0;
                } else if (a[i]== (w-1)) {ans = 1;

} else flag = 1;            } else//was borrow {if (a[i]==0) {ans
                = 0; } else if (a[i]==w-1| |
                A[i]==w-2) {ans = 1;
            } else flag = 1;
            }//cout<<ans<< "" <<flag<<endl;
        if (flag==1) break;
        } if (flag==0) {printf ("yes\n");
    } else printf ("no\n");
} return 0;
 }