还是手搓结构体舒服

#include <iostream>
#include <cstdio>
#include <memory.h>
using namespace std;
struct node{
	int num[2005];
	int len = 1;
	friend ostream &operator << (ostream &cout, node &a){
		for(int i = a.len; i >= 1; i--) cout << a.num[i];
		return cout;
	}
	void operator += (node &b){
        len = max(len, b.len);
		for(int i = 1; i <= len; i++){
			num[i] += b.num[i];
			if(num[i] >= 10){
				num[i + 1]++;
				num[i] -= 10;
			}
		}
		if(num[len + 1]) len++;
	}
	void init_1(){
		num[1] = 1;
	}
}dp[5005];
int main(){
	cin.tie(nullptr) -> sync_with_stdio(0);
	cout.tie(nullptr) -> sync_with_stdio(0);
	int n;
	cin >> n;
	dp[1].init_1();
	for(int i = 2; i <= n + 1; i++){
		dp[i] += dp[i - 1];
		dp[i] += dp[i - 2];
	}
	cout << dp[n + 1];

	return 0;
}