URAL1133. Fibonacci Sequence（二分）

刚开始还用记忆化推了下公式后来发现数是非常大的

二分然后就是精度错误中间值会很大

乱七八糟的改

 1 #include <iostream>
 2 #include<cstdio>
 3 #include<cstring>
 4 #include<algorithm>
 5 #include<stdlib.h>
 6 #include<cmath>
 7 #include<vector>
 8 using namespace std;
 9 #define LL long long
10 #define INF 2147483647
11 long double f[3010];
12 int main()
13 {
14     LL i,j,s1,s2,t,n,g;
15     cin>>i>>s1>>j>>s2>>n;
16     i+=1005;j+=1005;n+=1005;
17     if(i>j)
18     {
19         t = i;i = j;j = t;
20         t = s1;s1 = s2; s2 = t;
21     }
22     f[i] = s1;
23     f[j] = s2;
24     if(j!=i+1)
25     {
26         long double low = -INF,high = INF,m;
27         while(low<high)
28         {
29             m = (low+high)/2;
30             f[i+1] = m;
31             for(g = i+2 ; g < j ; g++)
32             {
33                 f[g] = f[g-1]+f[g-2];
34             }
35             long double tt = f[j-1]+f[j-2];
36             if(tt<s2)
37             low = m+1;
38             else if(tt>s2)
39             high = m-1;
40             else low=m,high=m;
41         }
42         f[i+1] = (low+high)/2;
43         for(g = i+2 ; g < j ; g++)
44         {
45             f[g] = f[g-1]+f[g-2];
46         }
47     }
48     if(n<i)
49     {
50         for(g = i-1 ; g >= n ; g--)
51             f[g] = f[g+2]-f[g+1];
52     }
53     else if(n>j)
54     {
55         for(g = j+1 ; g <= n ; g++)
56             f[g] = f[g-1]+f[g-2];
57     }
58     cout<<(LL)f[n]<<endl;
59     return 0;
60 }

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