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
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
#include <bits/stdc++.h>
using namespace std;

int n,t,wynik;
string s;

struct segment{int l; int w;};
struct compare
{
    bool operator()(segment const&A, segment const&B)
    {
        if(A.l==B.l)return A.w>B.w;
        return A.l<B.l;
    }
};
priority_queue<segment, vector<segment>, compare> Q;

void modify(int k)
{
    stack<segment> stos;
    while(Q.size()!=0)
    {
        segment y=Q.top();
        Q.pop();
        y.l=y.l-2*k;
        if(y.l>0)stos.push(y);
    }

    while(stos.size()!=0)
    {
        segment y=stos.top();
        stos.pop();
        Q.push(y);
    }
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin>>t;
    for(int e=1;e<=t;e++)
    {
        cin>>n;
        bool tab[n+10];
        cin>>s;
        tab[0]=1;
        for(int i=1;i<=n;i++)
        {
            if(s[i-1]=='0')tab[i]=0;
            else tab[i]=1;
        }

        int pocz=0,kon=0;

        for(int i=1;i<=n;i++)
        {
            if(tab[i]==0)
            {
                if(tab[i-1]==1)pocz=i;
                kon=i;
            }
            else
            {
                if(pocz!=0&&kon!=0)
                {
                    int k=2;
                    if(pocz==1)k--;
                    if(kon==n)k--;

                    segment x;
                    x.l=kon-pocz+1;
                    x.w=k;
                    if(k==1)x.l=x.l*2;
                    Q.push(x);
                    pocz=0;
                    kon=0;
               //     cout<<x.l<<" "<<x.w<<endl;
                }
            }
        }

        if(tab[n]==0)
        {
            int k=2;
            if(pocz==1)k--;
            if(kon==n)k--;

            segment x;
            x.l=kon-pocz+1;
            if(k==1)x.l=x.l*2;
            x.w=k;
            Q.push(x);
       //     cout<<x.l<<" "<<x.w<<endl;
            pocz=0;
            kon=0;
        }

        wynik=0;

        while(Q.size()!=0)
        {
            segment x=Q.top();
            Q.pop();
            if(x.w==1)
            {
                x.l=x.l/2;
            }
            wynik+=x.l;
            if(x.w==2&&x.l!=1)wynik--;
            modify(x.w);
        }
        cout<<n-wynik<<endl;
    }
}