Locked in the Past

#include<bits/stdc++.h>

using namespace std;

typedef long long llint;
typedef pair <int, int> pi;

const int MAXN = 1005;
const llint INF = 1000000000000000000LL;

llint n, k, x, y, sol = INF;
llint a[MAXN], val[MAXN];

int main () {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin >> n >> k;
    k++;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        val[i] = (a[i] - a[i - 1] + k) % k;
        x += val[i];
    }
    sort(val + 1, val + 1 + n);
    for (int i = n; i >= 1; i--) {
        x -= val[i];
        y += k - val[i];
        sol = min(sol, max(x, y));
    }
    cout << sol;
    return 0;
}