突然发现只要跟高精有关的题就基本没对过

# include<bits/stdc++.h>
using namespace std;
int main(){ 
	int m, n;
	cin >> m >> n;
	int f[4010] = {0}, a1[2005] = {1}, a2[2005] = {1}, len = 1;
	for(int i = 3; i <= n - m + 1; i++){
		for(int j = 0; j < len; j++){
			f[j] = a2[j] + a1[j];
			if(f[j] >= 10) f[j + 1] += f[j] / 10, f[j] %= 10;
		}
		if(f[len]) len++;
		for(int j = len - 1; j >= 0; j--) a2[j] = a1[j], a1[j] = f[j];		
	}
	for(int i = len - 1; i >= 0; i--) cout << f[i];
	return 0;
}