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#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

#define N 100005

int t;
int n;
char c;
int a[N];

bool beg;
int cur;
vector<pair<int, int>> zones;
int tim;
int ans;

auto cmp = [] (pair<int, int> a, pair<int, int> b) {
	return a.first * b.second > b.first * a.second;
};

int main(){
	cin.tie(0);
	ios_base::sync_with_stdio(0);

	cin >> t;

	while(t--){
		cin >> n;

		for(int i=0;i<n;i++){
			cin >> c;

			a[i] = (int)(c-'0');

			if(a[i] == 1){
				ans++;
				if(!beg){
					beg = true;
					if(cur > 0) zones.push_back({cur, 1});
				}
				else{
					if(cur > 0) zones.push_back({cur, 2});
				}
				cur = 0;
			}
			else{
				cur++;
			}
		}

		if(cur > 0) zones.push_back({cur, 1});

		sort(zones.begin(), zones.end(), cmp);

		/*
		for(auto p : zones){
			cout << p.first << " " << p.second << "\n";
		}*/

		for(auto z : zones){
			if(z.second == 1){
				ans += min(tim, z.first);
			}
			else if(z.second == 2){
				if(z.first - tim * 2 == 1){
					ans += 2*tim;
				}
				else{
					ans += min(2*tim + 1, z.first);
				}
			}
			tim += z.second; 
		}

		cout << ans << "\n";

		beg = false;
		cur = 0;
		zones.clear();
		tim = 0;
		ans = 0;
	}

	return 0;
}