#include <bits/stdc++.h>
using namespace std;
#define int long long
int t[4*200002];
void update(int i, int l, int r, int i1, int v){
if(l == r){
t[i] += v;
return;
}
int mid = (l + r)/2;
if(i1 <= mid){
update(i*2, l, mid, i1, v);
}else{
update(i*2+1, mid+1, r, i1, v);
}
t[i] = t[i*2] + t[i*2+1];
}
int query(int i, int l, int r, int l1, int r1){
if(l > r1 || l1 > r) return 0;
if(l1 <= l && r1 >= r){
return t[i];
}
int mid = (l+r)/2;
return (query(i*2, l, mid, l1, r1) + query(i*2+1, mid+1, r, l1, r1));
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
int n, q, s, tr; cin >> n >> q >> s >> tr;
vector<int> x(n+1);
for(int i = 0; i <= n; i++){
cin >> x[i];
}
int co = 0;
for(int i = 1; i <= n; i++){
if(x[i-1] < x[i]){
co -= s * abs(x[i-1] - x[i]);
}else{
co += tr * abs(x[i-1] - x[i]);
}
}
while(q--){
int l, r, c; cin >> l >> r >> c;
//l, l-1
if(l != 0){
int a, b;
a = x[l-1] + query(1, 0, n+1, 0, l-1);
b = x[l] + query(1, 0, n+1, 0, l);
if(a < b){
co += s * abs(a-b);
}else{
co -= tr * abs(a-b);
}
}
//r, r+1
if(r != n){
int a, b;
a = x[r] + query(1, 0, n+1, 0, r);
b = x[r+1] + query(1, 0, n+1, 0, r+1);
if(a < b){
co += s * abs(a-b);
}else{
co -= tr * abs(a-b);
}
}
update(1, 0, n+1, l, c);
update(1, 0, n+1, r+1, -c);
//l, l-1
if(l != 0){
int a, b;
a = x[l-1] + query(1, 0, n+1, 0, l-1);
b = x[l] + query(1, 0, n+1, 0, l);
if(a < b){
co -= s * abs(a-b);
}else{
co += tr * abs(a-b);
}
}
//r, r+1
if(r != n){
int a, b;
a = x[r] + query(1, 0, n+1, 0, r);
b = x[r+1] + query(1, 0, n+1, 0, r+1);
if(a < b){
co -= s * abs(a-b);
}else{
co += tr * abs(a-b);
}
}
cout << co << "\n";
}
return 0;
}
