func_code_string: #include <bits/stdc++.h>   const int Maxn = 50005;   int N, A[Maxn];   double L[Maxn], P[Maxn], Sum[Maxn], Ans;   using namespace std;   bool Cmp(const int &i, const int &j) {     return (L[i] * P[i] * (1 - P[j] / 100)) > (L[j] * P[j] * (1 - P[i] / 100));   }   int main() {     scanf( %d , &N);     for (int i = 1; i <= N; ++i) {       scanf( %lf%lf , &L[i], &P[i]);       A[i] = i;     }     sort(A + 1, A + 1 + N, Cmp);     for (int i = 1; i <= N; ++i) Sum[i] = Sum[i - 1] + L[A[i]] * P[A[i]];     for (int i = 1; i <= N; ++i) Ans += L[i] * 10000;     for (int i = 2; i <= N; ++i) Ans += (100 - P[A[i]]) * Sum[i - 1];     cout << setprecision(12) << setiosflags(ios ::fixed) << Ans / 10000 << endl;     return 0;   }   