PAT 1009 Product of Polynomials

佚名 6年前 (2019-04-10) 随笔 1837人围观抢沙发百度已收录

1009 Product of Polynomials （25 分)

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:

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K N1 aN1 N2 aN2 ... NK aNK

where K is the number of nonzero terms in the polynomial, Ni and aNi (,) are the exponents and coefficients, respectively. It is given that 1, 0.

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;
typedef long long ll;
#define maxnum 100005

double a[1005] = {0};
double b[1005] = {0};
double c[maxnum] = {0};


int main(){
    int n;cin >> n;
    int t;
    for(int i=0;i < n;i++){
        int x;double y;
        cin >> x >> y;
        a[x] = y;
        if(!i)t = x;
    }
    int m;cin >> m;
    int start;
    for(int i=0;i < m;i++){
        int x;double y;
        cin >> x >> y;
        b[x] = y;
        if(!i) start = x;
    }

    for(int i=0;i < t+5;i++){
        for(int j=0;j < start+5;j++){
            c[i+j] += a[i]*b[j];
        }
    }

    int cnt = 0;
    for(int i=0;i < maxnum;i++)if(c[i])cnt++;
    cout << cnt;

    for(int i=maxnum-1;i>=0;i--){
        if(c[i]) printf(" %d %.1lf",i,c[i]);
    }


    return 0;
}