Käännöt

#include <iostream>
using namespace std;
typedef long long ll;
const int MN = 1e5+100;
const ll MOD = 1e9+7;
ll sum1[MN];
ll sum2[MN];
ll sum3[MN];
ll getSum1(int a, int b) {
    if(b < a) return 0;
    return (sum1[b] - sum1[a-1])%MOD;
}
ll getSum2(int a, int b) {
    if(b < a) return 0;
    return (sum2[b] - sum2[a-1])%MOD;
}
ll getSum3(int a, int b) {
    if(b < a) return 0;
    return (sum3[b] - sum3[a-1])%MOD;
}
ll ex[MN];
int main() {
    string s;
    cin>>s;
    ll lol = 1;
    ex[0] = 1;
    for(int i = 1; i < MN; ++i) {
        ex[i] = ex[i-1]*10%MOD;
    }
    for(int i = 0; i < MN-1; ++i) {
        sum1[i+1] = sum1[i]*10+i+1;
        sum1[i+1] %= MOD;
        sum2[i+1] = sum2[i] + lol*(i+1);
        sum2[i+1] %= MOD;
        lol *= 10;
        lol %= MOD;
        sum3[i+1] = sum3[i]*10 + 1;
        sum3[i+1] %= MOD;
    }
    ll n = s.size();
    ll ans = 0;
    for(ll i = 1; i <= n; ++i) {
        int x = s[i-1] - '0';
        int a = i;
        int b = n-i+1;
        int c = min(a, b);
        ll d = getSum1(1, c);
        ll mid = n - 2*c+1;
        d *= ex[mid];
        d %= MOD;
        d += getSum3(1, mid)*c;
        d %= MOD;
        d *= ex[c-1];
        d %= MOD;
        d += getSum2(1, c-1);
        ans += d * x % MOD;
        ans += x * (((i-1)*i/2 + (n-i)*(n-i+1)/2)%MOD)%MOD*ex[n-i];
        ans %= MOD;
    }
    ans += MOD;
    ans %= MOD;
    cout<<ans<<'\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