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
115
116
117
118
119
120
121
122
#include <iostream>
#include <queue>
#include <algorithm>

using namespace std;

int main() {


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

		int n, right, left = -1, zeros = 0;
		priority_queue<int> q;
		char c;
		bool disease = false;
		cin >> n;
		cin.get(c);

		for (int j = 0; j < n; j++) {
			
			cin.get(c);
			if (c == '0') {
				zeros++;
			} else {
				if (left == -1) {
					left = zeros;
				} else if (zeros > 0) {
					q.push(zeros);
				}
				zeros = 0;
				disease = true;
			}
		}
		right = zeros;

		if (!disease) {
			cout << 0 << endl;
		} else {

			int d = 0;
			int vacined = 0;

			while (left - d > 0 || (!q.empty() && q.top() - 2*d > 0) || right - d > 0) {

				int ll = max(left - d, 0);
				int rr = max(right - d, 0);
				if (q.empty()) {
					if (ll > rr) {
						vacined += ll;
						left = 0;
					} else {
						vacined += rr;
						right = 0;
					}
				} else {
					int qq = max(q.top() - 2*d, 0);

					if (ll == 0 && rr == 0) {
						if (qq == 1 || qq == 2) {
							vacined += 1;
						} else {
							vacined += qq - 1;
							d++;
						}
						q.pop();
					} else if (ll == 0 && qq == 0) {
						vacined += rr;
						right = 0;
					} else if (rr == 0 && qq == 0) {
						vacined += ll;
						left = 0;
					} else if (ll == 0) {
						if (qq >= 4) {
							vacined += qq - 1;
							d++;
						} else {
							vacined += rr;
							right = 0;
						}
					} else if (rr == 0) {
						if (qq >= 4) {
							vacined += qq - 1;
							d++;
						} else {
							vacined += ll;
							left = 0;
						}
					} else if (qq == 0) {
						vacined += ll + rr - 1;
						left = 0;
						right = 0;
					} else {
						if (ll + rr > qq) {
							vacined += ll + rr - 1;
							left = 0;
							right = 0;
							d++;
							if (ll == 1 || rr == 1) {
								d--;
							}
						} else {
							if (qq == 1 || qq == 2) {
							vacined += 1;
						} else {
							vacined += qq - 1;
							d++;
						}
						q.pop();
						}
					}
				}
				d++;
			}

			cout << n - vacined << endl;
		}
	}

	return 0;
}