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POJ 3070 Fibonacci(矩阵快速幂)
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
Hint
As a reminder, matrix multiplication is associative, and the product of two 2 × 2 matrices is given by
.
Also, note that raising any 2 × 2 matrix to the 0th power gives the identity matrix:
.
Source
#include<iostream> #include<cstdio> #include<cstring> #include<algorithm> #include<vector> typedef long long LL; using namespace std; #define REPF( i , a , b ) for ( int i = a ; i <= b ; ++ i ) #define REP( i , n ) for ( int i = 0 ; i < n ; ++ i ) #define CLEAR( a , x ) memset ( a , x , sizeof a ) const int MOD=10000; typedef vector<int>vec; typedef vector<vec>mat; LL n; mat mul(mat A,mat B) { mat C(A.size(),vec(B[0].size())); REP(i,A.size()) { REP(j,B[0].size()) { REP(k,B.size()) C[i][j]=(C[i][j]+A[i][k]*B[k][j])%MOD; } } return C; } mat pow(mat A,LL n) { mat B(A.size(),vec(A.size())); REP(i,A.size()) B[i][i]=1; while(n>0) { if(n&1) B=mul(B,A); A=mul(A,A); n>>=1; } return B; } void work() { mat A(2,vec(2)); A[0][0]=1;A[0][1]=1; A[1][0]=1;A[1][1]=0; A=pow(A,n); cout<<A[1][0]<<endl; } int main() { std::ios::sync_with_stdio(false); while(cin>>n&&n!=-1) work(); return 0; }
POJ 3070 Fibonacci(矩阵快速幂)