标签：out iostream span cpp input while html clu ice
This time, you are supposed to find A×B where A and B are two polynomials.
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???? (,) are the exponents and coefficients, respectively. It is given that 1, 0.
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.
2 1 2.4 0 3.2
2 2 1.5 1 0.5
3 3 3.6 2 6.0 1 1.6
题意：
一元多项式的乘法。
main函数主要由3部分组成：ReadPoly(), MultPoly()和PrintPoly()。用到的数据结构有：链表。
难点：指针，指针的指针。
Code：
#include<iostream>
#include<algorithm>
#include<iomanip>
using namespace std;
typedef struct PolyNode *Polynomial;
struct PolyNode
{
double coef;
int expon;
Polynomial link;
};
void Attach(int expon, double coef, Polynomial* rear) {
Polynomial P = (Polynomial)malloc(sizeof(struct PolyNode));
P->expon = expon;
P->coef = coef;
P->link = NULL;
(*rear)->link = P;
(*rear) = P;
}
Polynomial ReadPoly() {
Polynomial p, pRear, t;
int e, N;
double c;
p = (Polynomial)malloc(sizeof(struct PolyNode));
cin >> N;
p->link = NULL;
pRear = p;
while(N--) {
cin >> e >> c;
Attach(e, c, &pRear);
}
t = p, p = p->link, free(t);
return p;
}
Polynomial MultPoly(Polynomial P1, Polynomial P2) {
Polynomial Rear, t, t1, t2, P;
int e;
double c;
if (P1 == NULL || P2 == NULL) return NULL;
t1 = P1, t2 = P2;
P = (Polynomial)malloc(sizeof(struct PolyNode));
P->link = NULL;
Rear = P;
while(t2) {
Attach(t1->expon + t2->expon, t1->coef * t2->coef, &Rear);
t2 = t2->link;
}
t1 = t1->link;
while (t1) {
t2 = P2; Rear = P;
while (t2) {
e = t1->expon + t2->expon;
c = t1->coef * t2->coef;
while (Rear->link && Rear->link->expon > e) Rear = Rear->link;
if (Rear->link && Rear->link->expon == e) {
if (Rear->link->coef + c) {
Rear->link->coef += c;
} else {
t = Rear->link;
Rear->link = t->link;
free(t);
}
} else {
t = (Polynomial)malloc(sizeof(struct PolyNode));
t->expon = e;
t->coef = c;
t->link = Rear->link;
Rear->link = t;
}
t2 = t2->link;
}
t1 = t1->link;
}
t = P; P = P->link; free(t);
return P;
}
void PrintPoly(Polynomial p) {
Polynomial t = p;
int len = 0;
while (t != NULL) {
len++;
t = t->link;
}
cout << len;
while(p != NULL) {
cout << " " << p->expon;
cout << " " << fixed << setprecision(1) << p->coef;
p = p->link;
}
}
int main() {
Polynomial p1, p2, pp;
p1 = ReadPoly();
p2 = ReadPoly();
pp = MultPoly(p1, p2);
PrintPoly(pp);
return 0;
}
标签：out iostream span cpp input while html clu ice
原文地址：https://www.cnblogs.com/ruruozhenhao/p/12584309.html
