折腾半天ac不了，试了图中的例子，非零项计数出错，还以为是浮点数比较出了问题，想
fabs()再与const float ZERO=1e-6比较判断是否为0
然鹅。。。
partially accected的主要原因是，只考虑了原先这个幂次的系数是不是0，没有在运算后在判断一下是否为0。
Screen Shot 2019-01-23 at 3.29.08 PM.png
附：两个测试例子
- 1 1000 0.1
1 0 0.2 - 2 3 1 2 -1
2 1 1 0 1
#include <cstdio>
#define N 1005
int main() {
int an, bn, ex, high_ex1, high_ex2, low_ex1, low_ex2;
float co, a_poly[N] = {0.0f}, b_poly[N] = {0.0f}, res[2 * N] = {0.0f};
scanf("%d%d%f", &an, &ex, &co);
high_ex1 = ex;
a_poly[ex] = co;
for (int i = 1; i < an; ++i) {
scanf("%d%f", &ex, &co);
a_poly[ex] = co;
}
low_ex1 = ex;
scanf("%d%d%f", &bn, &ex, &co);
high_ex2 = ex;
b_poly[ex] = co;
for (int i = 1; i < bn; ++i) {
scanf("%d%f", &ex, &co);
b_poly[ex] = co;
}
low_ex2 = ex;
int cnt_term = 0;
for (int j = low_ex1; j <= high_ex1; ++j) {
if (a_poly[j] != 0.0f)
for (int i = low_ex2; i <= high_ex2; ++i) {
if (b_poly[i] != 0) {
if (res[i + j] == 0.0f) {
cnt_term++;
}
res[i + j] += a_poly[j] * b_poly[I];
if (res[i + j] == 0.0f) {
cnt_term--;
}
}
}
}
printf("%d ", cnt_term);
for (int k = high_ex1 + high_ex2; cnt_term > 1 && k > low_ex1 + low_ex2; --k) {
if (res[k] != 0.0f) {
cnt_term--;
printf("%d %.1f ", k, res[k]);
}
}
printf("%d %.1f", low_ex1 + low_ex2, res[low_ex1 + low_ex2]);
return 0;
}
