URAL 1133. Fibonacci Sequence

题目链接

 #include <cstdio>
 #include <string>
 #include <cstring>
 #include <iostream>
 using namespace std;
 #define LL long long
 #define INF 2000000000
 LL p[];
 int main()
 {
     int i;
     LL a,fa,fb,b,n;
     LL str,mid,end;
     cin>>a>>fa>>b>>fb>>n;
     if(a > b)
     {
         swap(a,b);
         swap(fa,fb);
     }
     str = -INF;
     end = INF;
     while(str <= end)
     {
         mid = (str+end)/;
         int f1,f2;
         f1 = f2 = ;
         memset(p,-,sizeof(p));
         p[a+] = fa;
         p[a++] = mid;
         for(i = a+;i <= b;i ++)
         {
             p[i+] = p[i-+] + p[i-+];
             if(p[i+] > INF)
             {
                 f1 = ;
                 break;
             }
             if(p[i+] < -INF)
             {
                 f2 = ;
                 break;
             }
         }
         if(f1)
         end = mid - ;
         else if(f2)
         str = mid + ;
         else if(p[b+] == fb)
         break;
         else if(p[b+] > fb)
         end = mid - ;
         else if(p[b+] < fb)
         str = mid + ;
     }
     if(n <= b&&n >= a)
     ;
     else if(n < a)
     {
         p[a+] = fa;
         p[a++] = mid;
         for(i = a-;i >= n;i --)
         {
             p[i+] = p[i++] + p[i++];
         }
     }
     else
     {
         p[a+] = fa;
         p[a++] = mid;
         for(i = a+;i <= n;i ++)
         {
             p[i+] = p[i-+] + p[i-+];
         }
     }
     cout<<p[n+]<<endl;
     return ;
 }