【pat】b1010 一元多项式求导

#include<cstdio>
#include<vector>
using namespace std;
struct duo{
    int xishu,zhishu;
}M;
int main(){
    vector<duo> arr;//结构体向量
    while(scanf("%d %d",&M.xishu,&M.zhishu)!=EOF){
        M.xishu*=M.zhishu;
        M.zhishu--;
        if(M.zhishu>=0)
            arr.push_back(M);
    }
    if(arr.size()==0) printf("0 0");//如果结果为0
    else{
        for(int i=0;i<arr.size();i++){
            if(i!=0)printf(" ");
            printf("%d %d",arr[i].xishu,arr[i].zhishu);
        }
    }
    return 0;
}