````cpp
#include <bits/stdc++.h>
using namespace std;
int l,r,tmp,a[10],p,sum;
int main(){
cin>>l>>r;
for(int i=l;i<=r;i++){
p=0;
tmp=i;
while(tmp>0){
p++;
a[p]=tmp%10;
tmp/=10;
}
for(int j=1;j<=p;j++)
if(a[j]==2)
sum++;
}
cout<<sum;
return 0;
}
``````
by gaojizhe05 @ 2023-11-19 21:06:37
@[_Gary](/user/1113517) i<r -> i<=r
by gaojizhe05 @ 2023-11-19 21:08:08
@[_Gary](/user/1113517) 记得开 $long long$
by _d_h_f @ 2023-11-19 21:08:44
@[_Gary](/user/1113517) 区间包含l和r
by gaojizhe05 @ 2023-11-19 21:08:52
@[_d_h_f](/user/1057109) 跟longlong没关系吧
by gaojizhe05 @ 2023-11-19 21:09:51
@[_Gary](/user/1113517) 而且是
```
i<=r
```
by _d_h_f @ 2023-11-19 21:09:54
@[gaojizhe05](/user/699271) 好吧，只有五个点确实不用开 $long long$ ，反正开着也保险一些
by _d_h_f @ 2023-11-19 21:11:44
l <= r
by OIer_bcx @ 2023-11-19 21:12:36
@[_Gary](/user/1113517) 应该是 `l<=r`，不是 `l<r`。
第一个循环。
by 2021zjhs005 @ 2023-11-19 21:15:47
@[gaojizhe05](/user/699271) ,谢谢
by _Gary @ 2023-11-21 18:49:01