## 数论才是正解
```cpp
#include<bits/stdc++.h>
int t,n,ans;
int main(){
for(scanf("%d",&t);t;t--){
scanf("%d",&n);ans=n;
for(int i=7;i<=n;i++) for(int x=i;x;x/=10) if(x%10==7){ans--;break;}
printf("%d\n",ans);
}
return 0;
}
```
by Alphaban @ 2019-04-13 13:50:55
@[IcproX](/user/112109) 您的代码也超时了呢.....
by code_7 @ 2020-10-08 20:29:59