ABC C题对拍两小时无果，WA 4求助

#include<bits/stdc++.h>

#define int long long
#define In(x) freopen(x,"r",stdin)
#define Out(x) freopen(x,"w",stdout)

using namespace std;

int n;

const int N=35;

int a[N];

int Calc(int n){
	int ans=0;
	for(int i=1;i<n;i++) for(int j=1;j<=9;j++) ans+=pow(j,i-1);
	for(int j=1;j<a[n];j++) ans+=pow(j,n-1);
	int i=n-1;
	for(i=n-1;i>=1;i--){
		ans+=min(a[i],a[n])*pow(a[n],i-1);
		if(a[i]>=a[n]) break;
	}
	if(!i) ans++;
	return ans;
}

int Solve(int x){
	n=0;
	while(x) a[++n]=x%10,x/=10;
	return Calc(n);
}

signed main()
{
	In("A.in");Out("A.out");
	
	int l,r;cin>>l>>r;
	
	cout<<Solve(r)-Solve(l-1);
	return 0;
}