///
/// breakdown breakdown
///
#include <bits/stdc++.h>
#define Loop(x,l,r) for(ll x = ll(l); x < ll(r); ++x)
#define LoopR(x,l,r) for(ll x = ll(r)-1; x >= ll(l); --x)
typedef long long ll;
using namespace std;
const int N = 200'010;
ll fen[N];
void add(int r, ll x)
{
while(r > 0)
{
fen[r] += x;
r -= r&-r;
}
}
void add(int l, int r, ll x)
{
add(r, x);
add(l, -x);
}
ll get(int i)
{
++i;
ll ans = 0;
while(i < N){
ans += fen[i];
i += i&-i;
}
return ans;
}
int n, q;
ll s, t;
inline ll foo(ll x, ll y){return x < y? (x-y)*s: (x-y)*t;}
inline ll foo(int i){return i>n?0:foo(get(i-1),get(i));}
ll up(int l, int r, ll x)
{
ll ans = foo(l)+foo(r);
add(l,r,x);
ans = foo(l)+foo(r)-ans;
return ans;
}
int main()
{
ios::sync_with_stdio(false); cin.tie(0);
cin >> n >> q >> s >> t;
ll ans = 0;
Loop(i,0,n+1)
{
int x;
cin >> x;
if(i) ans += up(i,i+1,x);
}
while(q--)
{
int l, r, x;
cin >> l >> r >> x; ++r;
ans += up(l,r,x);
cout << ans << '\n';
}
}
