PAT1002 A+B for Polynomials

题目描述

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 N​1​​ a​N​1​​​​ N​2​​ a​N​2​​​​ ... N​K​​ a​N​K​​​​

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

Output Specification:

For each test case you should output the sum 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 to 1 decimal place.

Sample Input:

2 1 2.4 0 3.2
2 2 1.5 1 0.5

Sample Output:

3 2 1.5 1 2.9 0 3.2

题目求解

这道题不难，除了题目所提示的，还需要注意的是，两个多项式求和以后，系数和为0的项。

#include<iostream>
#include<stdio.h>
#include<algorithm>
#include<map>
#include<iomanip>

using namespace std;

int m[1002] = {0};
map<int, double> mm;

int main(){
    int k;  //k number of nonzero terms
    int n;
    double a;   //n is exponents, a is coefficients
    cin>>k;
    for(int i=0;i<k;i++){
        cin>>n>>a;
        if(m[n]==0){
            m[n] = 1;
            m[1001] += 1;
            mm[n] = a;
        }
        else{
            mm[n] += a;
        }
    }
    cin>>k;
    for(int i=0;i<k;i++){
        cin>>n>>a;
        if(m[n]==0){
            m[n] = 1;
            m[1001] += 1;
            mm[n] = a;
        }
        else{
            mm[n] += a;
        }
    }
    for(int i=1000;i>=0;i--){
        if(m[i]!=0&&mm[i]==0.0){
            m[1001]--;
        }
    }
    cout<<m[1001];
    for(int i=1000;i>=0;i--){
        if(m[i]!=0&&mm[i]!=0.0){
            cout<<" "<<i<<" "<<fixed<<setprecision(1)<<mm[i];
        }
    }
    cout<<endl;
    return 0;
}