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
#include "iostream"
#include "sstream"
#include "vector"
#include "algorithm"

int d[401][401];

int solve(const std::vector<std::string>& grid) {
    int n = grid.size();
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            d[i][j] = grid[i][j] == '0' ? 401 : 1;
            if (i == j) {
                d[i][i] = 0;
            }
        }
    }

    for (int k = 0; k < n; k++) {
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n ; j++) {
                d[i][j] = std::min(d[i][j], d[i][k] + d[k][j]);
            }
        }
    }

    int result = 401;
    for (int i = 0; i < n; i++) {
        for (int j = i + 1; j < n; j++) {
            int maxi = 0;
            for (int k = 0; k < n; k++) {
                for (int l = k + 1; l < n; l++) {
                    maxi = std::max(maxi, std::min(d[k][l], std::min(d[k][i] + d[j][l], d[k][j] + d[l][i])));
                }
            }
            result = std::min(result, maxi);
        }
    }
    return result;
}

int main() {
    int t;
    std::cin >> t;

    for (int i = 0; i < t; i++) {
        int n;
        std::cin >> n;
        std::vector<std::string> grid;
        for (int j = 0; j < n; j++) {
            std::string row;
            std::cin >> row;
            grid.push_back(row);
        }
        std::cout << solve(grid) << std::endl;
    }
    return 0;
}