#include "bits/stdc++.h" using namespace std; #define task "" #define ll long long #define endl '\n' #define fi first #define se second #define vall(a) (a).begin(), (a).end() #define sze(a) (int)a.size() #define pii pair<int, int> #define pll pair<ll, ll> #define ep emplace_back #define pb push_back #define pf push_front const ll mod = 1e9 + 7; const int N = 1e6 + 5; const ll oo = 1e18; ll n, a[N], d[N], pre[N], suf[N]; inline void solve() { for (int i = 2; i <= n; ++i) d[i] = (a[i] - a[i - 1]); for (int i = 2; i <= n; ++i) pre[i] = pre[i - 1] + max(0ll, (1 - d[i])); for (int i = n; i >= 2; --i) suf[i] = suf[i + 1] + max(0ll, (d[i] + 1)); ll ans = oo; for (int i = 1; i <= n; ++i) ans = min(ans, max(pre[i], suf[i + 1])); cout << ans; } inline void input() { cin >> n; for (int i = 1; i <= n; ++i) cin >> a[i]; return solve(); } int main() { if(fopen(task ".inp", "r")) { freopen(task ".inp", "r", stdin); freopen(task ".out", "w", stdout); } ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); input(); return 0; } //2911

Main.cpp: In function 'int main()':
Main.cpp:47:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   47 |         freopen(task ".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:48:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   48 |         freopen(task ".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~