The Fibonacci sequence of the offer

Title Description:

We all know that the Fibonacci sequence now requires you to enter an integer n, and you output the nth of the Fibonacci sequence. The Fibonacci sequence is defined as follows:

Input:

The input may contain multiple test samples, for each test case,

The input includes an integer n (1<=n<=70).

Output:

corresponding to each test case,

Outputs the value of the nth Xiang Feipo sequence.

Sample input:

3

Sample output:

2


Note: This topic uses recursion to do a lot of repetitive calculations, the efficiency is very low.
Code:

#include <iostream>using namespacestd;Long LongFibonacci (intN) {    if(n==0){        return 0; }    if(n==1){        return 1; }    Long Longprenum=0; Long Longcurnum=1; Long LongAnsnum;  for(intI=2; i<=n;++i) {Ansnum=prenum+Curnum; Prenum=Curnum; Curnum=Ansnum; }    returnAnsnum;} intMain () {intN;  while(cin>>N) {cout<<fibonacci (n) <<Endl; }    return 0;} /************************************************************** problem:1387 User:lcyvino language:c++ Re sult:accepted time:10 Ms memory:1520 kb****************************************************************/

The Fibonacci sequence of the offer