题解 | #跳台阶扩展问题# | C++

#include <iostream>
using namespace std;

class Solution{
 public:
  int countWays(int n) {
    int prefix = 0;
    int ans = 0;
    for (int i = 1; i<=n; i++) {
        ans = prefix + 1;
        prefix += ans;
    }
    return ans;
  }
};

int main() {
    int n;
    std::cin >> n;
    std::cout << Solution().countWays(n);
}
// 64 位输出请用 printf("%lld")