Description
In the Fibonacci integer sequence, F0 = 0, F1 = 1, and Fn = Fn − 1 + Fn − 2 for n ≥ 2. For example, the first ten terms of the Fibonacci sequence are:
0, 1, 1, 2, 3, 5, 8, 13, 21, 34, …
An alternative formula for the Fibonacci sequence is
.
Given an integer n, your goal is to compute the last 4 digits of Fn.
Input
The input test file will contain multiple test cases. Each test case consists of a single line containing n (where 0 ≤ n ≤ 1,000,000,000). The end-of-file is denoted by a single line containing the number −1.
Output
For each test case, print the last four digits of Fn. If the last four digits of Fn are all zeros, print ‘0’; otherwise, omit any leading zeros (i.e., print Fn mod 10000).
Sample Input
0 9 999999999 1000000000 -1
Sample Output
0 34 626 6875
#include<cstdio>
#include<string.h>
#define MOD 10000
using namespace std;
struct Mat{
long long a[5][5];
}A,B;
void init()
{
A.a[1][1] = A.a[1][2] = A.a[2][1] = 1;A.a[2][2] = 0;
B.a[1][1] = B.a[1][2] = B.a[2][1] = 1;B.a[2][2] = 0;
}
Mat Ma(Mat x,Mat y)
{
Mat t;
memset(t.a,0,sizeof(t.a));
for(int i = 1; i <= 2; i++)
for(int j = 1; j <= 2; j++){
if(x.a[i][j] == 0) continue;
for (int q = 1 ; q <= 2 ; q++)
t.a[i][q] = (t.a[i][q] + x.a[i][j] * y.a[j][q] % MOD) % MOD;
t.a[i][j] = t.a[i][j] % MOD;
}
return t;
}
void MatQuck(int k)
{
while(k){
if(k&1)
B = Ma(A,B);
A = Ma(A,A);
k >>= 1;
}
}
int main()
{
int f[5]={0,1,1,2,3};
long long n;
while(~scanf("%lld",&n)&&(n!=-1)){
if(n<5) printf("%d\n",f[n]);
else {
init();
MatQuck(n-4);
long long sum = 0;
for(int i = 1; i <= 2; i++)
for(int j = 1; j <= 2; j++)
sum = (sum + B.a[i][j]) % MOD;
printf("%lld\n",sum);
}
}
}