题干

C++实现

#include<iostream>
using namespace std;int f0(int n);
int f1(int n);int main() {int n;cin >> n;cout << f0(n) + f1(n);return 0;
}int f0(int n) {//末尾为0的串if (n == 1) {return 1;}else {return f0(n - 1) + f1(n - 1);}
}
int f1(int n) {//末尾为1的串if (n == 1) {return 1;}else {return f0(n - 1);}
}```