#include <bits/stdc++.h>
#define fi first
#define se second
#define pb push_back
#define ll long long
#define int long long
using namespace std;
typedef pair<int,int> pii;
typedef pair<int, pii> ipii;
const int MAXN = 2e5+10;
const int INF = 1e9;
const int MOD = 1e9+7;
int n, q, s, t;
int a[MAXN];
int up, dw;
int st[4*MAXN], laz[4*MAXN];
int bd(int id, int l, int r){
if(l==r) return st[id] = a[l];
return st[id] = bd(2*id, l, (l+r)/2) + bd(2*id+1, (l+r)/2+1, r);
}
void bnc(int id){
if(laz[id] == 0) return;
laz[2*id] += laz[id];
st[2*id] += laz[id];
laz[2*id+1] += laz[id];
st[2*id+1] += laz[id];
laz[id] = 0;
}
int que(int id, int l, int r, int x){
if(r<x || x<l) return 0;
if(l==r && l==x) return st[id];
bnc(id);
return que(2*id, l, (l+r)/2, x) + que(2*id+1, (l+r)/2+1, r, x);
}
int upd(int id, int l, int r, int x, int y, int p){
if(r<x || y<l) return st[id];
if(x<=l && r<=y){
laz[id] += p;
return st[id] += p;
}
bnc(id);
return st[id] = upd(2*id, l, (l+r)/2, x, y, p) + upd(2*id+1, (l+r)/2+1, r, x, y, p);
}
signed main(){
//ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
cin >> n >> q >> s >> t;
for(int i=0; i<=n; i++) cin >> a[i];
for(int i=1; i<=n; i++){
int te = a[i]-a[i-1];
if(te < 0) dw += te;
else up += te;
}
bd(1, 1, n);
for(int i=1; i<=q; i++){
int l, r, p; cin >> l >> r >> p;
int al = que(1, 1, n, l); int al1 = que(1, 1, n, l-1);
int te = al-al1;
if(te < 0) dw -= te;
else up -= te;
if(r!=n){
int ar = que(1, 1, n, r); int ar1 = que(1, 1, n, r+1);
te = ar1-ar;
if(te < 0) dw -= te;
else up -= te;
}
upd(1, 1, n, l, r, p);
//cout << al << ' ' << al1 << ' ' << ar1 << ' '<< ar << "ar\n";
al = que(1, 1, n, l);
te = al-al1;
if(te < 0) dw += te;
else up += te;
if(r!=n){
int ar = que(1, 1, n, r); int ar1 = que(1, 1, n, r+1);
te = ar1-ar;
if(te < 0) dw += te;
else up += te;
}
//cout << dw << ' ' << up << "dw\n";
cout << dw*(-t) + up*(-s) << '\n';
}
}
