#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int N = 2e5+5;
int n, q;
ll S, T, ans;
ll a[N];
struct FWtree
{
ll tree[N];
void update( int idx, ll v )
{
for( int i=idx;i<=n;i+=i&-i ) tree[i] += v;
}
ll query( int idx )
{
ll sum = 0;
for( int i=idx;i>0;i-=i&-i ) sum += tree[i];
return sum;
}
}fen;
ll cal( ll a, ll b )
{
return (a-b)*((a>b)?T:S);
}
int main()
{
ios_base::sync_with_stdio(0);cin.tie(0);
cin >> n >> q >> S >> T;
for( int i=0;i<=n;i++ )
{
cin >> a[i];
if(i>0) fen.update( i, a[i]-a[i-1] );
if(i>0) ans += cal( a[i-1], a[i] );
}
while( q-- )
{
int l, r;
ll x;
cin >> l >> r >> x;
ll a = cal( fen.query(l-1), fen.query(l) );
if( r<n ) a += cal( fen.query(r), fen.query(r+1) );
fen.update( l, x );
fen.update( r+1, -x );
ll b = cal( fen.query(l-1), fen.query(l) );
if( r<n ) b += cal( fen.query(r), fen.query(r+1) );
ans += b-a;
cout << ans << "\n";
}
return 0;
}
