PAT (Basic level) practise (Chinese) 1010. Derivation of one-element polynomial (25)

1010. One-element polynomial derivation (25) time limit of MS
Memory Limit 32000 KB
Code length limit 8000 B
The Standard of the Judgment procedure

The design function asks for the derivative of the unary polynomial.

Input format: Enter the polynomial non 0 coefficients and indices (integers with an absolute value of not more than 1000) in an exponential degradation manner. Numbers are separated by spaces.

Output format: The coefficients and indices of the derivative polynomial not 0 items are output in the same format as the input. Numbers are separated by spaces, but there are no extra spaces at the end. Input Sample:

3 4-5 2 6 1-2 0

Output Sample:

12 3-10 1 6 0

Submitting Code

#include <stdlib.h>
#include <string.h>
#include <iostream>

using namespace std;

int main ()
{
    int a,b;
    int flag = 0;
    b = 1;
    while (cin>>a>>b)
    {
        if (b>0)
            if (flag ==0)
            {
                cout<<a*b<< ' < <b-1;
                flag = 1;
            }
            else
                cout<< ' <<a*b<< ' <<b-1;
    }
    if (flag ==0)
        cout<< "0 0";
    System ("pause");
    return 0;
}