@[Rain2011](/user/574038)
```cpp
#include<bits/stdc++.h>
using namespace std;
int main(){
double n=2;
double d=2; //改double
int ans=0;
double a;
cin>>a;
while(n<a){
d=d*0.98; //改成*0.98（就是98%）
n=n+d;
ans+=1;
}
cout<<ans+1; //最后结果要加一
return 0;
}
```
by hexuchen @ 2023-09-29 23:28:30
@[hexuchen](/user/945742) 感谢大佬帮助
by Rain2011 @ 2023-09-29 23:43:28