How many 0's?

10 11
100 200
0 500
1234567890 2345678901
0 4294967295
-1 -1

1
22
92
987654304
3825876150

// Problem#: 1370
// Submission#: 2196597
// The source code is licensed under Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License
// URI: http://creativecommons.org/licenses/by-nc-sa/3.0/ // All Copyright reserved by Informatic Lab of Sun Yat-sen University
#include<stdio.h>
#include<iostream>
using namespace std;
long long get_ans(long long u){
long long tmp=1,ans=1,k=u/10;

while (k)
{
ans+=(k-1)*tmp;
if (u-tmp*k*10+1>=tmp)
ans+=tmp;
else
ans+=u-tmp*k*10+1;
tmp*=10;
k/=10;
}
return ans;
}
// 截断，先算出来从1----n   1----m-1   之后就可以知道一共有多少个0了
int main(){

long long ans,m,n;

while (1)
{
cin>>m>>n;
if (m<0) break;

ans=get_ans(n);
if (m>0) ans-=get_ans(m-1);
cout<<ans<<endl;
}

return 0;
}

#include <iostream>
using namespace std;
long long pow10[]={1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000};
long long num0(long long n){
long long i;
long long cnt=1+n/10;
if(n<0)
return 0;
for(i=1; pow10[i]<=n/10; i++)
{
long long left=(n/10)/pow10[i];
long long mid =( n/pow10[i] )%10;
long long rit =n%pow10[i];
if(mid==0)
cnt+=(left-1)*pow10[i] + rit+1;
else
cnt+=left*pow10[i];
}
return cnt;
}

int main()
{
long long m, n;
while(cin>>m>>n && m>=0){
cout<<num0(n)-num0(m-1)
<<endl;
}
return 0;
}