【PAT 甲級】1009 Product of Polynomials (25分)（模拟）

​​1009 Product of Polynomials (25分)​​

題目

分析

#include <bits/stdc++.h>
using namespace std;
#define db(x) cout<<x<<endl

typedef long long ll;
const int INF = 0x3f3f3f;
const int N = 2e3 + 10;
const ll mod = 2147483648;

struct node {
  int x;
  double y;
} a[N], b[N];

int n, m, cnt, minn = INF;
double ans[N];

int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) scanf("%d %lf", &a[i].x, &a[i].y);
  scanf("%d", &m);
  for (int i = 0; i < m; i++) scanf("%d %lf", &b[i].x, &b[i].y);
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      if (a[i].y * b[j].y == 0) continue;
      ans[a[i].x + b[j].x] += a[i].y * b[j].y;
      minn = min(minn, a[i].x + b[j].x);
    }
  }
  for (int i = 0; i < N; i++) if (ans[i]) cnt++;
  printf("%d ", cnt);
  for (int i = N - 1; i >= minn; i--) {
    if (ans[i]) {
      printf("%d %.1f%c", i, ans[i], " \n"[i==minn]);
    }
  }
  return 0;
}