This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int rnd(int l,int r)
{
    return l+rng()%(r-l+1);
}
#define fasty ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define forinc(x,a,b) for(int x=a;x<=b;x++)
#define fordec(x,a,b) for(int x=a;x>=b;x--)
#define iii pair<ii,int>
#define fi first
#define se second
#define ii pair<int,int>
#define getbit(x,i) ((x>>(i))&1)
#define batbit(x,i) (x|(1ll<<(i)))
#define tatbit(x,i) (x&~(1<<(i)))
#define endl '\n'
#define pb push_back
#define int long long
const int N = 1e6 + 10;
int n, t[N];
int f[N][23];
int lg[N];
int dp[N];
int get(int l, int r)
{
    int p = lg[r-l+1];
    return max(f[l][p] , f[r - (1<<p) + 1][p]);
}
int cost(int j, int i)
{
    return dp[j] + get(j+1,i)*(n-j);
}
int inc=1;
int decc=1;
main()
{
    //freopen("task.inp" , "r" , stdin);
    fasty;
    cin >> n;
    forinc(i,1,n)
    {
        cin >> t[i];
        f[i][0] = t[i];
    }
    forinc(i,1,n-1)
    {
        if(t[i] > t[i+1]) inc=0;
        if(t[i] < t[i+1]) decc=0;
    }
    forinc(i,2,n) lg[i] = lg[i/2] + 1;
    forinc(j,1,20)
    {
        for(int i=1 ; i + (1<<j) - 1 <= n ; i++)
        {
            f[i][j] = max(f[i][j-1] , f[i + (1<<(j-1) )][j-1]);
        }
    }
    if(n<=7000)
    {
        memset(dp , 127, sizeof dp);
        dp[0]=0;
        forinc(i,1,n)
        {
            fordec(j,i-1,0) dp[i] = min(dp[i] ,cost(j,i));
        }
        cout << dp[n];
        return 0;
    }
    if(decc == 1)
    {
        int sum=0;
        int res = t[1] * n;
        cout << res << "\n";
        return 0;
    }
}
Compilation message (stderr)
Discharging.cpp:37:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   37 | main()
      | ^~~~
Discharging.cpp: In function 'int main()':
Discharging.cpp:73:13: warning: unused variable 'sum' [-Wunused-variable]
   73 |         int sum=0;
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