PAT - 1010. 一元多项式求导 (25)

#include <iostream>
#include <vector>
using namespace std;
int main()
{
    vector<int> p;
    int x;
    while (cin>>x)
    {
        p.push_back(x);
    }
    int p_size=p.size();
    if(p_size!=0)  // 0 denote no element in p, and will print "0 0" like p_size==2.
    {
        for(int i=0;i<p_size;i=i+2)
        {
            p[i]=p[i]*p[i+1];
            p[i+1]=p[i+1]-1;
            if (p[i]!=0)
            {
                if(i!=0)cout<<' ';
                cout<<p[i]<<' '<<p[i+1];
            }
            else
            {
                if(p_size==2)
                    cout<<"0 0";
            }
        }
    }
    else
    {
        cout<<"0 0";
    }
    system("pause");
    return 0;
}