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#include <algorithm>
#include <iostream>
#include <string.h>

using namespace std;

#define N 100000

int intervals[(N + 1) * 2];
int edges[2];

int solve() {
  int n, i = -1, j;
  int d, maxd = 0, aktd;
  int saved = 0, vacc = 0;
  char c;

  cin >> n;
  memset(intervals, 0, sizeof(intervals));
  for (j = 0; j < n; j++) {
    cin >> c;
    if (c == '0')
      continue;
    d = j - i - 1;
    if (i == -1) {
      d *= 2;
      edges[0] = d;
    }
    i = j;
    intervals[d] += 1;
    maxd = max(d, maxd);
  }
  if (i == -1)
    return 0;
  d = (n - i - 1) * 2;
  edges[1] = d;
  intervals[d] += 1;
  maxd = max(d, maxd);

  for (d = maxd; d > 0; d--) {
    if (intervals[d] == 0)
      continue;
    div_t dd = div(d, 2);
    for (i = 0; i < 2 && intervals[d] > 0 && (aktd = dd.quot - vacc) > 0; i++) {
      if (d != edges[i])
        continue;
      intervals[d] -= 1;
      saved += aktd;
      vacc += 1;
    }
    while (intervals[d] > 0 && (aktd = d - 2 * vacc) > 0) {
      vacc += min(aktd, 2);
      saved += max(aktd - 1, 1);
      intervals[d] -= 1;
    }
  }
  return n - saved;
}

int main() {
  ios_base::sync_with_stdio(0);
  int t;
  cin >> t;
  for (int k = 0; k < t; k++) {
    cout << solve() << endl;
  }
  return 0;
}