#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const int N = 2e5;
int n,q,s,t;
int a[N+5];
int S[N+5],B=2,S1[N+5],lz[N+5];
ll ans = 0;
bool op(int x,int y){
if(x < y) swap(x,y);
return (x >= 0 && y < 0);
}
int get(int x){
return (a[x] >= 0 ? a[x] + lz[x / B] : a[x] - lz[x / B]);
}
void cal(int x,int ty){
int cur = get(x);
if(x < n){
int nxt = get(x + 1);
// cout << cur << '.' << nxt << '\n';
if(cur < nxt) ans -= ty * (nxt - cur) * s;
else ans += ty * (cur - nxt) * t;
}
if(x > 0){
int pre = get(x - 1);
// cout << pre << '.' << cur << '\n';
if(pre < cur) ans -= ty * (cur - pre) * s;
else ans += ty * (pre - cur)* t;
}
}
void upd(int x,int val){
cal(x,-1);
// cout << ans << "pha1\n";
a[x] = a[x] + val;
// a[x] = (a[x] >= 0 ? a[x] + val : a[x] - val);
cal(x,1);
// cout << ans << "pha2\n";
}
void cal1(int x,int y,int ty){
int cur = get(x);
int cur1 =get(y);
// cout << cur << ',' << cur1 << "\n";
if(cur < cur1) ans -= ty * (cur1 - cur) * s;
else ans += ty * (cur - cur1) * t;
}
void upd1(int x, int y,int val,int ty){
if(y > n) return;
cal1(x,y,-1);
if(ty == 0) a[y] =a[y] + val;
else a[x] = a[x] + val;
cal1(x,y,1);
if(ty == 0) a[y] =a[y] - val;
else a[x] = a[x] - val;
}
int main(){
ios::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 = 0 ; i < n ; ++i){
if(a[i] < a[i + 1]){
ans -= (a[i + 1] - a[i]) * s;
}
else{
ans += (a[i] - a[i + 1]) * t;
}
// if(i / B == (i + 1) / B && op(a[i],a[i + 1])){
// if(a[i] >= 0) S[i / B]++;
// else S1[i / B]++;
// }
}
// cout << ans << "!\n";
while(q--){
int l,r,x;
cin >> l >> r >> x;
for(int i = l ; i <= r ; ++i){
if(i % B == 0 && i + B - 1 <= r){
upd1(i-1,i,x,0);
upd1(i + B - 1,i+B,x,1);
lz[i/B] += x;
// cout << S[i/B] << '?' << S1[i/B] << '.' << lz[i/B] << '.' << i + B - 1 << ',' << a[i + B - 1] << '.' << get(i + B - 1) << '\n';
i += B - 1;
}
else{
upd(i,x);
}
}
cout << ans << '\n';
}
return 0;
}
