Käännöt

#include <iostream>

#define ll long long
const ll M=1e9+7;

using namespace std;


string s;
ll hlp[101010][10];
ll cnt[10];

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cin>>s;
	int n=s.size();
	for (int i=0;i<n;i++) {
		ll dig=s[i]-'0';
		cnt[dig]++;
	}
	for (int i=0;2*i<n;i++) {
		int k=n-i-1;
		for (int j=1;j<10;j++) {
			hlp[i][j]+=cnt[j];
			if (i!=k) hlp[k][j]+=cnt[j];
			if (i>0) {
				hlp[i][j]+=hlp[i-1][j];
				if (i!=k) hlp[k][j]+=hlp[k+1][j];
			}
			hlp[i][j]%=M;
			hlp[k][j]%=M;
		}
		cnt[s[i]-'0']--;
		cnt[s[k]-'0']--;
	}
/*	for (int i=0;i<n;i++) {
		for (int j=1;j<10;j++) cout<<hlp[i][j]<<" ";
		cout<<endl;
	}
*/
	ll res=0;
	ll a=1;
	for (ll i=n-1;i>=0;i--) {
		for (int j=1;j<10;j++) {
			ll tmp=hlp[i][j]*j;
			tmp%=M;
			tmp*=a;
			tmp%=M;
			res+=tmp;
			res%=M;
		}
		ll tmp=((ll)(n-i))*(n-i-1)/2;
		tmp+=i*(i+1)/2;
		tmp%=M;
		tmp*=s[i]-'0';
		tmp*=a;
		res+=tmp;
		res%=M;
		a*=10;
		a%=M;
	}
	cout<<res<<"\n";
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: ACCEPTED

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED