fibonacci分治求法

fibonacci 数列

F(n) = F(n-1) + F(n-2)
F(1) = F(0) = 1

#include<stdio.h>
#include<iostream>
using namespace std;

#define max 65535
unsigned long long feb_nums[max];

int fibonacci(unsigned long long int n){
    if(n == 0 || n == 1){
        return 1;
    }
    return fibonacci(n-1)+fibonacci(n-2);
}

int fibonacci_h(unsigned long long n){
    // 分治算法
    if(n == 0 || n == 1){
        return feb_nums[n] = 1;
    }
    if(feb_nums[n] != max){
        return feb_nums[n];
    }
    return feb_nums[n] = fibonacci_h(n-1) + fibonacci_h(n-2);
}

int main()
{
    int n = 100;

    for(int i = 0; i < max; i++){
        feb_nums[i] = max;
    }
    cout << fibonacci_h(n) << endl;
    for(int i = 0; i < n; i++){
        cout << feb_nums[i] << " ";
    }
    cout << endl;
    return 0;
}