This C++ code defines functions to read input, calculate remainders and absolute differences of numbers modulo a given value k, find the maximum of these values, and output the minimum maximum. It takes as input the number of test cases t, reads the input n and k for each test case, calculates remainders and differences of an array of n numbers modulo k, finds the maximum of each, and outputs the minimum of the two maxima.

1. #include <bits/stdc++.h>
using namespace std;
#define int long long
#define pb push_back
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
void debugMode()
{
#ifndef ONLINE_JUDGE
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
}
void solve()
{
int n, k;
cin >> n >> k;
vector<int> arr(n);
vector<int> rem(n), rem2(n);
for (auto &it : arr)
{
cin >> it;
}
for (int i = 0; i < n; i++)
{
rem[i] = arr[i] % k;
rem2[i] = abs(k - rem[i]);
}
int maxi1 = INT_MIN;
int maxi2 = INT_MIN;
for (int i = 0; i < n; i++)
{
maxi1 = max(maxi1, rem[i]);
}
for (int i = 0; i < n; i++)
{
maxi2 = max(maxi2, rem2[i]);
}
cout << min(maxi1, maxi2) << endl;
}

2. int32_t main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
debugMode();
int t;
cin >> t;
while (t--)
{
solve();
}
return 0;
}