1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
#include <bits/stdc++.h>
using namespace std;

const int N = 1e6 + 5;

#define st first
#define nd second

typedef pair<int,int> pun;
typedef long long ll;

int test() {
	int n;
	string s;
	cin >> n >> s;
	int pref = 0;
	int suf = 0;
	while (pref < n && s[pref] == '0') pref ++;
	while (suf < n && s[n-suf-1] == '0') suf ++;
	if (pref == n) return 0;
	int res = 0;
	vector<int> breaks;
	breaks.push_back(pref);
	breaks.push_back(suf);
	int x = 0;
	for (int i = pref; i < n - suf; i ++) {
		if (s[i] == '1') {
			breaks.push_back(x / 2);
			breaks.push_back((x+1) / 2);
			x = 0;
		}
		else x++;
	}
	breaks.push_back(x);
	sort(breaks.begin(), breaks.end());
	reverse(breaks.begin(), breaks.end());
	int y = 0;
	for (int x : breaks) {
		if (x > y) {
			res += x - y;
			y++;
		}
	}
	return n-res;
}

int main() {
	ios_base::sync_with_stdio(false);
	int t;
	cin >> t;
	for (int i = 0; i < t; i ++) {
		cout << test() <<"\n";
	}
}