Go: package main

/*
フィボナッチ数列
*/

import (
	"bufio"
	"bytes"
	"fmt"
	"log"
	"os"
	"strconv"
	"strings"
)

func fibWithMemo(n int, memo map[int]int) int {
	if n == 0 || n == 1 {
		return 1
	}
	if val, ok := memo[n]; ok {
		return val
	}
	memo[n] = fibWithMemo(n-1, memo) + fibWithMemo(n-2, memo)
	return memo[n]
}

func fib(n int) int {
	memo := make(map[int]int)
	return fibWithMemo(n, memo)
}

func main() {
	scanner := makeScanner(1024)
	n := eGetInt(scanner)
	fmt.Println(fib(n))
}

////////////////////////////////////////////////////////////////////////////////
// ライブラリ
////////////////////////////////////////////////////////////////////////////////
func makeScanner(maxByte int) *bufio.Scanner {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Buffer(make([]uint8, 0, 8192), maxByte)
	return scanner
}
func makeWordScanner() *bufio.Scanner {
	scanner := makeScanner(8192)
	scanner.Split(bufio.ScanWords)
	return scanner
}
func eGetLine(r *bufio.Scanner) string {
	if r.Scan() {
		return r.Text()
	}
	err := r.Err()
	if err != nil {
		log.Fatal(err)
	}
	// EOF
	return ""
}
func eGetInt(r *bufio.Scanner) int {
	line := eGetLine(r)
	return eAtoi(line)
}
func eGetFields(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Fields(line)
}
func eGetInts(r *bufio.Scanner) []int {
	fields := eGetFields(r)
	ints := make([]int, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoi(fields[i])
	}
	return ints
}
func eGetChars(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Split(line, "")
}
func eAtoi(s string) int {
	n, err := strconv.Atoi(s)
	if err != nil {
		log.Fatal(err)
	}
	return n
}

type ints []int

func (s ints) String() string {
	var buf bytes.Buffer
	buf.WriteString("[")
	sep := ""
	for _, v := range s {
		buf.WriteString(fmt.Sprintf("%s%d", sep, v))
		sep = ", "
	}
	buf.WriteString("]")
	return buf.String()
}

func reverse(a ints) ints {
	r := make(ints, len(a))
	for i := 0; i < len(a); i++ {
		r[i] = a[len(a)-1-i]
	}
	return r
}
func max(a ints) (int, bool) {
	if len(a) == 0 {
		return 0, false
	}
	m := a[0]
	for _, e := range a {
		if e > m {
			m = e
		}
	}
	return m, true
}
func min(a []int) int {
	m := a[0]
	for _, v := range a {
		if v < m {
			m = v
		}
	}
	return m
}

func sum(a ints) int {
	if len(a) == 0 {
		return 0
	}
	sum := 0
	for _, e := range a {
		sum += e
	}
	return sum
}
func find(n int, a ints) int {
	for i, v := range a {
		if n == v {
			return i
		}
	}
	return -1
}

C++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<ll, ll>;

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int N;
    cin >> N;

    if (N < 2) {
        cout << 1 << endl;
        exit(0);
    }
    vector<ll> fib(N + 1);
    fib.at(0) = 1;
    fib.at(1) = 1;
    for (int i = 2; i <= N; ++i) {
        fib.at(i) = fib.at(i - 1) + fib.at(i - 2);
    }

    cout << fib.at(N) << endl;

    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

typedef long long ll;


int fib(int n){
    if(n==0)return 1;
    else if(n==1)return 1;
    else return fib(n-1)+fib(n-2);
}


int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    cout << fib(n) << endl;
}

C++: #define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
#include <cstdlib>
#include <string>
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <vector>
#include <set>
#include <random>
#include <map>

using namespace std;

int fibArray[50];

void makeFibArray() {
    for (int i = 2; i <= 46; i++) {
	fibArray[i] = fibArray[i - 1] + fibArray[i - 2];
    }
}

int main() {

    //cin.tie(0);
    //ios::sync_with_stdio(false);

    int n; scanf("%d", &n);
    fibArray[0] = 1;
    fibArray[1] = 1;
    makeFibArray();
    printf("%d\n", fibArray[n]);


    return 0;

}

C++: #include<iostream>

using namespace std;

int fib(int n);

int main() {
  int n;

  //入力
  cin >> n;

  //出力
  cout << fib(n) << endl;

  return 0;
}

int fib(int n){
  if(n==0 || n == 1){
    return 1;
  }else{
    return fib(n-1) + fib(n-2);
  }
}

C++: #include<iostream>
using namespace std;

int main() {
    int n; cin >> n;
    int F[50];
    F[0] = F[1] = 1;
    for (int i = 2; i <= n; i++) {
        F[i] = F[i - 1] + F[i - 2];
    }
    
    cout << F[n] << endl;
    
    return 0;
}

C++: #include <stdio.h>

using namespace std;

long long Fibonacci[43] = {0};

long long fibo(int n){
	if(n == 0)	return 1;
	else if(n == 1)	return 1;
	else{
		if(Fibonacci[n-1] != 0 && Fibonacci[n-2] != 0){
			//Do nothing
		}else if(Fibonacci[n-1] != 0){
			Fibonacci[n-2] = fibo(n-2);
		}else if(Fibonacci[n-2] != 0){
			Fibonacci[n-1] = fibo(n-1);
		}else{
			Fibonacci[n-1] = fibo(n-1);
			Fibonacci[n-2] = fibo(n-2);
		}
		return Fibonacci[n-1] + Fibonacci[n-2];
	}
}

int main(){
	int n;
	scanf("%d",&n);
	printf("%lld\n",fibo(n));
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MOD = 1e9+7,MAX = 1e5;

int hibo[50];

int fibo(int i)
{	
	if(i==0||i==1)return hibo[i] = 1;
	if(hibo[i]!=0)return hibo[i];
	return hibo[i] = fibo(i-1)+fibo(i-2);
}

int main()
{
	int n;cin >> n;
	cout<<fibo(n)<<endl;
	return 0;
}

C++: #include <iostream>
using namespace std;
 
int main() {
	int fib[45]={1,1},i;
for(i=1;i<=44;i++){
fib[i]=fib[i-1]+fib[i-2];
}
	return 0;
}