pat1009 Product of Polynomials

#include<cstdio>#include<iostream>#include<algorithm>#include<vector>#include<queue>#include<string>#include<cstring>#include<cmath>#include<map>using namespace std;double a[1005],b[1005],c[2005];int main(){int n,m,i,j,x,nm;double y;while(scanf("%d",&n)!=EOF){nm = 0;for(i = 0;i<n;i++){scanf("%d%lf",&x,&y);a[x] = y;}scanf("%d",&m);for(i = 0;i<m;i++){scanf("%d%lf",&x,&y);b[x] = y;}for(i = 0;i<=1000;i++){if(a[i]==0)continue;for(j = 0;j<=1000;j++){if(b[j]==0)continue;c[i+j]+=a[i]*b[j];}}for(i = 2000;i>=0;i--)if(c[i]!=0)nm++;printf("%d",nm);for(i = 2000;i>=0;i--){if(c[i]==0)continue;printf(" %d %.1lf",i,c[i]);}printf("\n");}return 0;}