func_code_string: #include <bits/stdc++.h>   const long long mod = 1000000007;   const long long Inf = 1e9;   using namespace std;   long long a, b, d, k, t;   double f(long long x) {     double res = 0;     res = (double)x * (double)a +           (double)(max(x / k - (x % k == 0 ? 1 : 0), (long long)0)) * (double)t +           (double)(d - x) * (double)b;     return res;   }   int main() {     scanf( %I64d%I64d%I64d%I64d%I64d , &d, &k, &a, &b, &t);     long long l = 1, r = d;     double ans = 1e18;     while (r - l > 2000000) {       long long x1 = l + (r - l) / 3;       long long x2 = r - (r - l) / 3;       if (f(x1) > f(x2))         l = x1;       else if (f(x1) < f(x2))         r = x2;       else {         l = x1;         r = x2;       }     }     for (long long i = l; i <= r; ++i) {       ans = min(ans, f(i));     }     printf( %0.lf , ans);     return 0;   }   