多项式乘法 | 1009 Product of Polynomi

1009 Product of Polynomials

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;
}