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#include <cstdio>
#include <cmath>
#include <iostream>
#include <algorithm>
#include <queue>
#include <list>
#include <vector>
#include <map>
#include <set>
#include <string>
#include <cstring>
#include <cassert>
#include <limits.h>

using namespace std;

typedef long long LL;
typedef long double LD;

typedef vector<int> VI;
typedef pair<int,int> PII;
#define REP(i,n) for(int i=0;i<(n);i++)
#define FOR(i,a,b) for(VAR(i,a);i<=(b);++i)
#define FORD(i,a,b) for(VAR(i,a);i>=(b);--i)
#define FORE(a,b) for(VAR(a,(b).begin());a!=(b).end();++a)
#define VAR(a,b) __typeof(b) a=(b)
#define SIZE(a) ((int)((a).size()))
#define ALL(x) (x).begin(),(x).end()
#define CLR(x,a) memset(x,a,sizeof(x))
#define ZERO(x) memset(x,0,sizeof(x))
#define S(t,i) scanf("%" ## t, &i)
#define SI(i) scanf("%d", &i)

const int INF=INT_MAX;
const int MAXN=100000+5;

int n, t;
char c[MAXN];

int main() {
    ios_base::sync_with_stdio(0);
    
    auto my_comp = [](const pair<int, int>& z1, const pair<int, int>& z2) {
        return 2*z2.first/z2.second > 2*z1.first/z1.second;
    };
    
    SI(t);
    REP(i, t) {
        SI(n);
        scanf(" ");
        fread(c, sizeof(c[0]), n, stdin);
        
        int result = 0;
        priority_queue<pair<int,int>, std::vector<pair<int,int>>, decltype(my_comp)> segments(my_comp);
        
        int l=0;
        int speed=1;
        REP(i, n) {
            if (c[i] == '1') {
                if (l>0) {
                    segments.push(make_pair(l, speed));
                }
                l=0;
                speed=2;
                result++;
            } else {
                l++;
            }
        }
        if (l > 0 && l < n) {
            segments.push(make_pair(l, 1));
        }
        int day = 0;
        while (!segments.empty()) {
            pair<int, int> p = segments.top();
//            printf("%d %d %d\n", p.first, p.second, min(p.first, p.second * day));
            segments.pop();
            result += min(p.first, p.second * day);
            if (p.second == 2) {
                int rest = p.first - p.second * day - 1;
                if (rest > 0) {
                    result -= day;
                    segments.push(make_pair(rest + day, 1));
                }
            }
            day++;
        }
        
        printf("%d\n", result);
    }
    
    
    return 0;
}