#include <bits/stdc++.h> using namespace std; void solve() { int n; cin >> n; vector<string> a(n); for (string &s: a) cin >> s; vector dist(n, vector<int>(n, 1e9)); for (int i = 0; i < n; i++) { for (int j = 0; j < n; j++) { if (a[i][j] == '1') dist[i][j] = 1; if (i == j) dist[i][j] = 0; } } for (int k = 0; k < n; k++) { for (int i = 0; i < n; i++) { for (int j = 0; j < n; j++) { dist[i][j] = min(dist[i][j], dist[i][k] + dist[k][j]); } } } int res = n; for (int i = 0; i < n; i++) { for (int j = 0; j < i; j++) { int diam = 0; for (int a = 0; a < n; a++) { for (int b = 0; b < a; b++) { int cur = dist[a][b]; cur = min(cur, dist[a][i] + dist[j][b]); cur = min(cur, dist[a][j] + dist[i][b]); diam = max(diam, cur); if (diam >= res) break; } if (diam >= res) break; } res = min(res, diam); } } cout << res << '\n'; } int main() { int tc; cin >> tc; while (tc--) solve(); }
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 | #include <bits/stdc++.h> using namespace std; void solve() { int n; cin >> n; vector<string> a(n); for (string &s: a) cin >> s; vector dist(n, vector<int>(n, 1e9)); for (int i = 0; i < n; i++) { for (int j = 0; j < n; j++) { if (a[i][j] == '1') dist[i][j] = 1; if (i == j) dist[i][j] = 0; } } for (int k = 0; k < n; k++) { for (int i = 0; i < n; i++) { for (int j = 0; j < n; j++) { dist[i][j] = min(dist[i][j], dist[i][k] + dist[k][j]); } } } int res = n; for (int i = 0; i < n; i++) { for (int j = 0; j < i; j++) { int diam = 0; for (int a = 0; a < n; a++) { for (int b = 0; b < a; b++) { int cur = dist[a][b]; cur = min(cur, dist[a][i] + dist[j][b]); cur = min(cur, dist[a][j] + dist[i][b]); diam = max(diam, cur); if (diam >= res) break; } if (diam >= res) break; } res = min(res, diam); } } cout << res << '\n'; } int main() { int tc; cin >> tc; while (tc--) solve(); } |