1009 Product of Polynomials

标签：coefficient Product exponent int cin Polynomials ita -- 1009

This time, you are supposed to find A×B where A and B are two polynomials.

Input Specification:

Each input file contains one test case. Each case occupies 2 lines, and each line contains the information of a polynomial:

K N1​ aN1​​ N2​ aN2​​ ... NK​ aNK​​

where K is the number of nonzero terms in the polynomial, Ni​ and aNi​​ (i=1,2,⋯,K) are the exponents and coefficients, respectively. It is given that 1≤K≤10, 0≤NK​<⋯<N2​<N1​≤1000.

Output Specification:

For each test case you should output the product of A and B in one line, with the same format as the input. Notice that there must be NO extra space at the end of each line. Please be accurate up to 1 decimal place.

Sample Input:

2 1 2.4 0 3.2
2 2 1.5 1 0.5

 

Sample Output:

3 3 3.6 2 6.0 1 1.6

#include<bits/stdc++.h>
using namespace std;
int main(){
    int k;
    int exponent;
    float coefficient;
    vector<pair<int,float>> a,b;
    float result[2005]={0};
    int count=0;
    cin>>k;
    while(k--){
        cin>>exponent>>coefficient;
        a.push_back(make_pair(exponent,coefficient));
    }
    cin>>k;
    while(k--){
        cin>>exponent>>coefficient;
        b.push_back(make_pair(exponent,coefficient));
    }
    vector<pair<int,float>>::iterator ita,itb;
    for(ita=a.begin();ita<a.end();++ita){
        for (itb=b.begin();itb<b.end();++itb){
            result[itb->first+ita->first]+=itb->second*ita->second;
        }
    }
    for(int i=0;i<2005;++i){
        if (result[i]!=0){
            ++count;
        }
    }
    cout<<count;
    for(int i=2004;i>=0;--i){
        if (result[i]!=0){
            cout<<" "<<i<<" ";
            printf("%.1f",result[i]);
        }
    }
}

一开始result数组开了1005，跑了一下直接段错误，这才反应过来指数相加后应该开到2000+

标签：coefficient,Product,exponent,int,cin,Polynomials,ita,--,1009
From： https://www.cnblogs.com/coderhrz/p/16586771.html