In mathematical terms, the normal sequence F(n) of Fibonacci numbers is defined by the recurrence relation
F(n)=F(n-1)+F(n-2)
with seed values
F(0)=1, F(1)=1
In this Gibonacci numbers problem, the sequence G(n) is defined similar
G(n)=G(n-1)+G(n-2)
with the seed value for G(0) is 1 for any case, and the seed value for G(1) is a random integer t, (t>=1). Given the i-th Gibonacci number value G(i), and the number j, your task is to output the value for G(j)
Input
There are multiple test cases. The first line of input is an integer T < 10000 indicating the number of test cases. Each test case contains 3 integers i, G(i) and j. 1 <= i,j <=20, G(i)<1000000
Output
For each test case, output the value for G(j). If there is no suitable value for t, output -1.
Sample Input
4 1 1 2 3 5 4 3 4 6 12 17801 19
Sample Output
2 8 -1 516847
思路:设第二位为t,可以知道第i为得公式,然后算出t,后面就是fibbonacci的计算方法
#include<iostream>
#include<stdio.h>
using namespace std;
int main()
{
int t;
cin>>t;
while(t--){
int a,b,c,i,T;
cin>>a>>b>>c;
unsigned long long s1[23],s2[23];
s1[0]=1; s1[1]=0;
s2[0]=0; s2[1]=1;
for(i=2;i<=20;i++){
s1[i]=s1[i-1]+s1[i-2];
s2[i]=s2[i-1]+s2[i-2];
}
if(a==1)
T=b;
else
if((b-s1[a])%s2[a]==0)
T=(b-s1[a])/s2[a];
else
T=-1;
unsigned long long f[23];
f[0]=1;
f[1]=T;
if(T<1)
cout<<"-1"<<endl;
else
{
for(i=2;i<=c;i++)
f[i]=f[i-1]+f[i-2];
//cout<<f[c]<<endl;
printf("%lld\n",f[c]);
}
}
return 0;
}