#include <bits/stdc++.h>  // This will work only for g++ compiler. 


#define for0(i, n) for (int i = 0; i < (int)(n); ++i) // 0 based indexing
#define for1(i, n) for (int i = 1; i <= (int)(n); ++i) // 1 based indexing
#define forc(i, l, r) for (int i = (int)(l); i <= (int)(r); ++i) // closed interver from l to r r inclusive
#define forr0(i, n) for (int i = (int)(n) - 1; i >= 0; --i) // reverse 0 based.
#define forr1(i, n) for (int i = (int)(n); i >= 1; --i) // reverse 1 based

//short hand for usual tokens
#define pb push_back
#define fi first
#define se second

// to be used with algorithms that processes a container Eg: find(all(c),42)
#define all(x) (x).begin(), (x).end() //Forward traversal
#define rall(x) (x).rbegin, (x).rend() //reverse traversal

// traversal function to avoid long template definition. Now with C++11 auto alleviates the pain.
#define tr(c,i) for(__typeof__((c)).begin() i = (c).begin(); i != (c).end(); i++)

// find if a given value is present in a container. Container version. Runs in log(n) for set and map
#define present(c,x) ((c).find(x) != (c).end())

//find version works for all containers. This is present in std namespace.
#define cpresent(c,x) (find(all(c),x) != (c).end())

// Avoiding wrap around of size()-1 where size is a unsigned int.
#define sz(a) int((a).size())


using namespace std;

// Shorthand for commonly used types
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef long long ll;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef double ld;

void solve() 
{
    ll n;
    cin >> n;
    ll arr[n];
    for(ll i=0; i<n; i++)
    {
        cin >> arr[i];
    }
    if(n == 1)
    {
        cout<<arr[0]<<"\n";
        return;
    }
    ll ans = 0;
    if(arr[0] > arr[1])
    {
        ans+=arr[0]-arr[1];
        arr[0] = arr[1];
        
    }
    ans += arr[0];
    for(ll i=1;i<n-1;i++)
    {
        ll temp = max(arr[i-1], arr[i+1]);
        if(arr[i] > temp)
        {
            ans+=arr[i]-temp;
            arr[i] = temp;
            
        }
        ans += abs(arr[i] - arr[i-1]);
    }
    if(arr[n-1] > arr[n-2])
    {
        ans += arr[n-1] - arr[n-2];
        arr[n-1] = arr[n-2];
    }
    ans += abs(arr[n-1] - arr[n-2]);
    ans+=arr[n-1];
    cout<<ans<<"\n";
}
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.precision(10);
    cout << fixed;
    
    
    ll t;
    cin>>t;
    while(t--)
        solve();
    return 0;
    
}