Экономия по времени - C++ - Ответ 8024156

#include <iostream>
#include <fstream>
#include <cstdio>
 
using namespace std;
 
int Fib(unsigned int x)
{
    if (x <= 1) return 1;
    else return Fib(x - 1) + Fib(x - 2);
}
 
int main()
{
    ifstream cin("fib.in");
    ofstream cout("fib.out");
    int Fibonacci;
    cin >> Fibonacci;
    cout << Fib(Fibonacci);
    return 0;
}

#include <iostream>
#include <fstream>
#include <cstdio>
 
using namespace std;
 
unsigned long fib(unsigned int n) {
    if (n == 0) return 0;
    unsigned long previous = 0;
    unsigned long current = 1;
    for (unsigned int i = 1; i < n; ++i) {
        unsigned long next = previous + current;
        previous = current;
        current = next;
    }
    return current;
}
int main()
{
    ifstream cin("fib.in");
    ofstream cout("fib.out");
    int Fibonacci;
    cin >> Fibonacci;
    cout << fib(Fibonacci+1);
    return 0;
}