func_code_string: #include <bits/stdc++.h>   using namespace std;   const int MAX = 4e5 + 10;   int n, a[MAX];   int f(int x) {     vector<int> v(n);     for (int i = 0; i < n; ++i) {       v[i] = (a[i] == -1 ? x : a[i]);     }     int ret = 0;     for (int i = 0; i < n - 1; ++i) {       ret = max(ret, abs(v[i] - v[i + 1]));     }     return ret;   }   void solve() {     cin >> n;     for (int i = 0; i < n; ++i) cin >> a[i];     long long beg = 0, end = 1e9;     while (end - beg > 3) {       long long mid1 = (2 * beg + end) / 3;       long long mid2 = (beg + 2 * end) / 3;       int f1 = f(mid1);       int f2 = f(mid2);       if (f1 > f2) {         beg = mid1 + 1;       } else if (f1 <= f2) {         end = mid2 - 1;       }     }     int ans = 1e9, ind;     for (int i = beg; i <= end; ++i) {       int t = f(i);       if (t < ans) {         ans = t;         ind = i;       }     }     cout << ans <<     << ind <<   n ;   }   int main() {     int q;     cin >> q;     while (q--) {       solve();     }   }   