专题三 · 1013

Posted 2022-12-10 suamfadmp

代码及解释

#include <iostream>

long long fibs[50] = 0, 1, 2, 3, 4;

// 又双叒叕是递推数列

int main() 
    int n;
    int flag = 4;

    while (std::cin >> n && n) 
        if (n <= flag) 
            std::cout << fibs[n] << std::endl;
         else 
            for (int i = flag + 1; i <= n; ++i)
                fibs[i] = fibs[i - 1] + fibs[i - 3];

            std::cout << fibs[n] << std::endl;
        
    
    return 0;