Laskutoimitus

#include <iostream>
using namespace std;
typedef long long ll;
const int Z = 1e9+7;
int main() {
	string s;cin>>s;
	ll asum = 0;
	ll bsum = 0;
	ll bval = 1;
	ll csum = 0;
	ll cval = 0;
	int ac = 0;
	int bc = 0;
	int cc = 0;
	ll res=0;
	for(char c: s) {
		if (c=='*' || c=='+') {
			bval *= cval;
			bval %= Z;
			bsum = csum + cval * bsum;
			bsum %= Z;
			bc += cc;
			cc = 0;
			csum = 0;
			cval = 0;
			if (c=='+') {
				//cout<<"+ "<<asum<<' '<<bsum<<' '<<bval<<'\n';
				asum = bsum + bval * asum;
				asum %= Z;
				bsum = 0;
				bval = 1;
				ac += bc;
				bc = 0;
			}
		}
		if (c!='+' && c!='*') {
			int d = c-'0';
			csum = 10*csum + (cc+1)*d;
			csum %= Z;
			cval = 10*cval + d;
			cval %= Z;
			cc++;
			//cout<<"csum "<<csum<<' '<<cval<<" ; "<<ac<<' '<<asum<<'\n';
			//cout<<"parts: "<<csum<<' '<<cval*bsum<<' '<<cval*bval*ac<<"+"<<asum<<'\n';

			res += csum + cval * bsum + cval * bval%Z * ac + asum;
			res %= Z;
		}
	}
	cout<<res<<'\n';
}

Test 1

Group: 1, 2, 6

Verdict: WRONG ANSWER

Test 2

Group: 1, 2, 6

Verdict: WRONG ANSWER

Test 3

Group: 1, 2, 3, 4, 5, 6

Verdict: ACCEPTED

Test 4

Group: 2, 6

Verdict: WRONG ANSWER

Test 5

Group: 2, 6

Verdict: WRONG ANSWER

Test 6

Group: 2, 3, 4, 5, 6

Verdict: ACCEPTED

Test 7

Group: 6

Verdict: WRONG ANSWER

Test 8

Group: 6

Verdict: WRONG ANSWER

Test 9

Group: 3, 4, 5, 6

Verdict: ACCEPTED

Test 10

Group: 4, 6

Verdict: WRONG ANSWER

Test 11

Group: 4, 6

Verdict: WRONG ANSWER

Test 12

Group: 5, 6

Verdict: ACCEPTED

Test 13

Group: 5, 6

Verdict: ACCEPTED