#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int maxn=2e5+5;
int n,q,s,t;
int a[maxn];
ll T[4 * maxn][2];
void prop(int nd){
if(!T[nd][1]) return;
T[nd<<1][0] += T[nd][1];
T[nd<<1][1] += T[nd][1];
T[nd<<1 | 1][0] += T[nd][1];
T[nd<<1 | 1][1] += T[nd][1];
T[nd][1] = 0;
}
void upd(int a,int b,int val,int l,int r,int nd){
if(r < a or l > b) return;
if(l >= a and r <= b){
T[nd][0] += val;
T[nd][1] += val;
return;
}
int md = (l + r) >> 1;
prop(nd);
upd(a,b,val,l,md,nd<<1);
upd(a,b,val,md+1,r,nd<<1 | 1);
}
ll tap(int pos,int l,int r,int nd){
if(l == r) return T[nd][0];
prop(nd);
int md = (l + r) >> 1;
if(pos <= md) return tap(pos,l,md,nd<<1);
return tap(pos,md+1,r,nd<<1 | 1);
}
int main(){
ios::sync_with_stdio(false);
cin.tie(0);
cin >> n >> q >> s >> t;
for(int i = 0;i <= n;i++){
cin >> a[i];
upd(i,i,a[i],0,n,1);
}
ll jog = 0;
for(int i = 0;i < n;i++){
if(a[i + 1] > a[i]) jog -= 1ll * s * (a[i + 1] - a[i]);
else jog += 1ll * t * (a[i] - a[i + 1]);
}
// cout<<jog<<'\n';
while(q--){
int l,r,x; cin >> l >> r >> x;
ll lft = tap(l-1,0,n,1);
ll cep = tap(l,0,n,1);
ll sag = tap(r,0,n,1);
ll rgt = tap(r + 1,0,n,1);
// cout<<lft<<' '<<cep<<' '<<sag<<' '<<rgt<<'\n';
if(lft < cep) jog += 1ll * s * (cep - lft);
else jog -= 1ll * t * (lft - cep);
if(r + 1 <= n){
if(sag < rgt) jog += 1ll * s * (rgt - sag);
else jog -= 1ll * t * (sag - rgt);
}
upd(l,r,x,0,n,1);
if(lft < cep + x){
jog -= 1ll * s * (cep + x - lft);
}
else jog += 1ll * t * (lft - cep - x);
if(r + 1 <= n){
if(rgt > sag + x){
jog -= 1ll * s * (rgt - x - sag);
}
else jog += 1ll * t * (sag + x - rgt);
}
cout<<jog<<'\n';
}
}
