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给定n，求斐波那契数列第n项对1e9+7取模的值

code

//求Fib  矩阵快速幂 
#include <bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 7;
typedef long long ll;
ll n;
struct Matrix {
	ll m[3][3];
	Matrix() {
		memset(m, 0, sizeof(m));
	}
	Matrix operator *(const Matrix &x) const {
		Matrix ret;
		for (register int i = 1; i <= 2; ++i)
			for (register int j = 1; j <= 2; ++j)
				for (register int k = 1; k <= 2; ++k)
					ret.m[i][j] = (ret.m[i][j] + m[i][k] * x.m[k][j]) % mod;
		return ret; 
	}
} a, base;
void qpow(ll p) {
	while (p) {
		if (p & 1) a = a * base;
		base = base * base;
		p >>= 1;
	}
}
int main() {
	scanf("%lld", &n);
	if (n <= 2) {
		puts("1");
		return 0;
	}
	base.m[1][1] = base.m[1][2] = base.m[2][1] = 1;
	a.m[1][1] = a.m[1][2] = 1;
	qpow(n - 2);
	printf("%lld\n", a.m[1][1] % mod);
	return 0;
}