Bittijono

#include <cstdint>
#include <bits/stdc++.h>


// Rediscovering basic stuff
// YE BOI
int main() {
	std::string input;
	std::cin >> input;

	uint64_t count = 0;

	uint64_t bonus = 0;
//	std::vector<uint8_t> verticals;
	// Bonus is the count of EVEN verticals
	uint64_t zeroCount = 0;

	uint64_t verticalsSize = 0;
	uint64_t evenVerticals = 0; // oddVerticals = verticalsSize - evenVerticals;

	for (char c : input) {
		++verticalsSize;
		++evenVerticals;
		// verticals.push_back(1);
		if (c == '0') {
			++zeroCount;
			count += zeroCount + bonus; // bonus meme
		} else {
			zeroCount = 0;
			bonus = 0;
			// Haha, swap em, kek
			evenVerticals = verticalsSize - evenVerticals;
			//for (unsigned i = 0; i < verticals.size(); ++i) {
			//	verticals[i] ^= 1;
			//	if (verticals[i] == 1) {
			//		bonus += 1;
			//	}
			//}
			bonus = evenVerticals;
			count += bonus;
		}
	}

	std::cout << count << std::endl;

	return 0;
}

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: 1

Verdict: ACCEPTED

Test 7

Group: 1

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED

Test 11

Group: 2

Verdict: ACCEPTED

Test 12

Group: 2

Verdict: ACCEPTED

Test 13

Group: 2

Verdict: ACCEPTED

Test 14

Group: 2

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED

Test 16

Group: 3

Verdict: ACCEPTED

Test 17

Group: 3

Verdict: ACCEPTED

Test 18

Group: 3

Verdict: ACCEPTED

Test 19

Group: 3

Verdict: ACCEPTED

Test 20

Group: 3

Verdict: ACCEPTED

Test 21

Group: 3

Verdict: ACCEPTED