#include<bits/stdc++.h> #include <ext/pb_ds/assoc_container.hpp> #include <ext/pb_ds/tree_policy.hpp> using namespace __gnu_pbds; using namespace std; template<class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>; template<class T, class U> using ordered_map = tree<T, U, less<T>, rb_tree_tag, tree_order_statistics_node_update>; #define ll long long #define MOD 1000000007 #define MAXN 2e5 #define SIZE 314 #define pb push_back ll power(ll a, ll b){ if (b == 0) return 1; ll res = power(a, b / 2); if (b % 2 == 1) return res * res % MOD * a % MOD; return res * res % MOD; // if (b % 2 == 1) return res * res * a; // return res * res; } int main(){ ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); // while(1){ int n, t; cin >> n >> t; vector<int> nums(n); int minNum = 1e9, maxNum = 1; for (int i = 0; i < n; i++){ cin >> nums[i]; nums[i] %= t; minNum = min(minNum, nums[i]); maxNum = max(maxNum, nums[i]); } int ans = (maxNum - minNum + 1) / 2; for (int i = 0; i < n; i++){ if (nums[i] <= t / 2){ minNum = max(minNum, nums[i] + t); } } ans = min(ans, (minNum - maxNum + 1) / 2); cout << ans << "\n"; //} return 0; }