Kertoma

#include<iostream>
#include<vector>
#include<cmath>
#include<string>

using namespace std;

void pienihaku(vector<long long> v) {
	long long a = 0;
	long long b = 0;
	long long c = 0;
	for (long long i = 0; i < 10; i++) {
		for (long long j = 0; j < v[i]; j++) {
			a += c * pow(10, b);
			b++;
		}
		c++;
	}

	long long x = 2;
	long long y = 2;
	while (y <= a) {
		if (y * (x + 1) <= a) {
			x++;
			y *= x;
		}
		else break;
	}
	cout << x;
}

int main() {
	vector<long long> v(10);
	long long t = 0;

	for (int i = 0; i < 10; i++) {
		cin >> v[i];
		t += v[i];
	}

	if (t < 18) pienihaku(v);

	long long x = 2;
	long long numerot = 0;
	long long edellinen = 2;
	

	while (numerot < t) {
		x++;
		long long y = edellinen * x;
		if (trunc(log10(y)) + 1 > 5) {
			numerot += (trunc(log10(y)) + 1) - 5;
			edellinen = stoi(to_string(y).substr(0, 5));
		}
		else {
			edellinen = y;
			if (trunc(log10(y)) + 1 > numerot) numerot = trunc(log10(y)) + 1;
		}
	}
	
	cout << x;
}

Test 1

Group: 1, 2, 3

Verdict: WRONG ANSWER

Test 2

Group: 1, 2, 3

Verdict: WRONG ANSWER

Test 3

Group: 1, 2, 3

Verdict: WRONG ANSWER

Test 4

Group: 1, 2, 3

Verdict: WRONG ANSWER

Test 5

Group: 1, 2, 3

Verdict: ACCEPTED

Test 6

Group: 1, 2, 3

Verdict: ACCEPTED

Test 7

Group: 2, 3

Verdict: ACCEPTED

Test 8

Group: 2, 3

Verdict: ACCEPTED

Test 9

Group: 2, 3

Verdict: ACCEPTED

Test 10

Group: 2, 3

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: WRONG ANSWER

Test 15

Group: 3

Verdict: WRONG ANSWER

Test 16

Group: 3

Verdict: WRONG ANSWER