Stand on Zanzibar

#include <iostream>
using namespace std;

int main() {
	int T;
	cin >> T;
	while (T--) {
		int res = 0;
		int last = 1;
		int cur;
		cin >> cur;
		while (cur != 0) {
			if (last*2 < cur) res += cur-last*2;
			last = cur;
			cin >> cur;
		}
		cout << res << endl;
	}
}

Test 1

Verdict: ACCEPTED