二分搜索 Codeforces Round #218 (Div. 2) C. Hamburgers

题目传送门

 /*
     题意：一个汉堡制作由字符串得出，自己有一些原材料，还有钱可以去商店购买原材料，问最多能做几个汉堡
     二分：二分汉堡个数，判断此时所花费的钱是否在规定以内
 */
 #include <cstdio>
 #include <algorithm>
 #include <cmath>
 using namespace std;

 typedef long long ll;
 const int MAXN = 1e2 + ;
 const int INF = 0x3f3f3f3f;
 char ham[MAXN];
 ll nb, ns, nc;
 ll pb, ps, pc;
 ll b, s, c;
 ll m;

 bool check(ll x)  {
     ll cost = ;
     if (b * x > nb) cost += (b * x - nb) * pb;
     if (s * x > ns) cost += (s * x - ns) * ps;
     if (c * x > nc) cost += (c * x - nc) * pc;
     return cost <= m;
 }

 int main(void)  {       //Codeforces Round #218 (Div. 2) C. Hamburgers
     scanf ("%s", &ham);
     scanf ("%I64d%I64d%I64d", &nb, &ns, &nc);
     scanf ("%I64d%I64d%I64d", &pb, &ps, &pc);
     scanf ("%I64d", &m);
     b = s = c = ;
     for (int i=; ham[i]; ++i)    {
         if (ham[i] == 'B')    b++;
         else if (ham[i] == 'S')   s++;
         else    c++;
     }
     ll l = , r = 1e13;
     while (l +  < r)   {
         ll mid = (l + r) >> ;
         if (check (mid))    l = mid;
         else    r = mid;
     }
     printf ("%I64d\n", l);

     return ;
 }