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>
#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <string>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <iomanip>
#include <utility>
#include <tuple>
#include <functional>
#include <bitset>
#include <cassert>
#include <complex>
#include <stdio.h>
#include <time.h>
#include <numeric>
#include <unordered_map>
#include <unordered_set>

using namespace std;

#define vv vector< vector< int > >
#define ll long long
#define ALL(a) (a).begin(), (a).end()
const long long mod = 1000000000 + 7;
const long long INF = 9e18;
const double PI = 3.14159265358979323846;

ll gcd(ll a, ll b){if (b == 0) return a;return gcd(b, a % b);}
ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }

int dx[4] = {1, -1, 0, 0};
int dy[4] = {0, 0, 1, -1};


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

C++: #include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <iostream>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <stack>
#include <list>
#include <queue>
#include <deque>
#include <algorithm>
#include <numeric>
#include <utility>
#include <complex>
#include <functional>
#include <climits>

using namespace std;
int T[100];
int fibo(int n) {
    if(T[n] != 0) return T[n];
    T[n] = fibo(n-1) + fibo(n-2);
    return T[n];
}
int main() {
    T[0] = T[1] = 1;
    int n;
    cin >> n;
    cout << fibo(n) << endl;
}

C++: #include <iostream>
#include <vector>

int Fibonacci( int n, std::vector<int>& v ){
    if( !n || n == 1 ){
        if( !v[n] ){
            v[n] = 1;
        }
        return v[n];
    }else{
        if( !v[n] ){
            v[n] = Fibonacci( n-1, v ) + Fibonacci( n-2, v );
        }
        return v[n];
    }
}

int main(){
    int n;
    std::cin.tie(0);
    std::cin >> n;

    std::vector<int> fib(n+1, 0);
    
    std::cout << Fibonacci( n, fib ) << std::endl;
}

C++: #include<bits/stdc++.h>
using namespace std;
int main(){
    int n; cin >> n;
    int f[50];
    f[0] = 1;
    f[1] = 1;
    for(int i = 2; i < 50; i++) f[i] = f[i-1] + f[i-2];
    cout << f[n] << endl;
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
int dx[4] = {1,0,-1,0};
int dy[4] = {0,-1,0,1};
vector<long long> ans(50,-1);
long long fib(int n){
    if(ans[n]!=-1) return ans[n];
    if(n==0 || n==1) return ans[n] = 1;
    return ans[n] = fib(n-1)+fib(n-2);
}
int main(void){
    int n;cin >> n;
    cout << fib(n) << endl;
    return 0;
}

C++: #include <stdio.h>

int fi(int a) {
  return (a == 0 || a == 1) ? 1 : fi(a - 1) + fi(a - 2);
}

int main(void) {
  int n;
  scanf("%d", &n);
  printf("%d\n", fi(n));
  return 0;
}

C++: 


/**
 *      purpose : 
 *      author  : kyomukyomupurin
 *      created : 
**/

// input/output
#include <iostream>
#include <fstream>
#include <sstream>
// container class
#include <array>
#include <deque>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <vector>
// math, algorithm
#include <algorithm>
#include <cmath>
#include <complex>
#include <numeric>
// etc
#include <bitset>
#include <cassert>
#include <cctype>
#include <cstring>
#include <chrono>
#include <iomanip>
#include <random>
#include <utility>
// using-directive
using namespace std;
// alias template
using int64 = long long;
using vi = vector<int>;
using vl = vector<int64>;
using pii = pair<int, int>;
using pll = pair<int64, int64>;
// text macro replacement
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define print(x) cout << (x) << '\n'
#define debug(x) cerr << #x << ": " << (x) << '\n'
#define dbg(v) for (size_t _ = 0; _ < v.size(); ++_){cerr << #v << "[" << _ << "] : " << v[_] << '\n';}
// variadic template
template<typename T> inline void chmin(T &a, T b) {if (a > b) a = b; return;}
template<typename T> inline void chmax(T &a, T b) {if (a < b) a = b; return;}
// constant
const int INF = (1<<30) - 1;
const int64 INF64 = (1LL<<62) - 1;
const int MOD = 1000000007;

int64 fib[50];

int main(){
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);

  int n; cin >> n;

  fib[0] = 1; fib[1] = 1;
  for (int i = 2; i < 50; ++i) {
    fib[i] = fib[i - 1] + fib[i - 2];
  }

  cout << fib[n] << '\n';

  return 0;
}

C++: #include <iostream>

using namespace std;

typedef long long signed int ll;

constexpr ll NIL = -20000000000;

ll fib(int n) {
    if(n < 2) return n;
    return fib(n-1) + fib(n-2);
}

int main() {
    int n;
    cout << fib(n) << endl;
}