#include <bits/stdc++.h>
#define st first
#define nd second
#define mp make_pair
#define pb push_back
#define sol (k+k)
#define sag (k+k+1)
#define orta ((bas+son)/2)
#define N 200005
using namespace std;
typedef long long ll;
ll n, q, s, t, l, r, x, ans, a[N], b[N], seg[4*N];
void bu(ll k, ll bas, ll son){
if(bas == son){
seg[k] = a[bas];
return;
}
bu(sol, bas, orta);
bu(sag, orta + 1, son);
}
ll qu(ll k, ll bas, ll son, ll x){
if(x == 0)
return 0;
if(bas == son)
return seg[k];
if(x <= orta)
return seg[k] + qu(sol, bas, orta, x);
return seg[k] + qu(sag, orta + 1, son, x);
}
void up(ll k, ll bas, ll son, ll x, ll y, ll z){
if(bas > y or son < x)
return;
if(bas >= x and son <= y){
seg[k] += z;
return;
}
up(sol, bas, orta, x, y, z);
up(sag, orta + 1, son, x, y, z);
}
int main() {
// freopen("in.txt", "r", stdin);
// freopen("out.txt", "w", stdout);
scanf("%lld %lld %lld %lld",&n ,&q ,&s ,&t);
for(ll i = 0; i <= n; i++)
scanf("%lld",a + i);
for(ll i = 1; i <= n; i++){
if(a[i] > a[i - 1])
b[i] = -s * (a[i] - a[i - 1]);
else
b[i] = t * (a[i - 1] - a[i]);
ans += b[i];
}
bu(1, 1, n);
while(q--){
scanf("%lld %lld %lld",&l ,&r ,&x);
ans -= b[r + 1] + b[l];
up(1, 1, n, l, r, x);
ll a1 = qu(1, 1, n, l - 1);
ll a2 = qu(1, 1, n, l);
ll a3 = qu(1, 1, n, r);
ll a4 = qu(1, 1, n, r + 1);
if(a2 > a1)
b[l] = -s * (a2 - a1);
else
b[l] = t * (a1 - a2);
if(a4 > a3)
b[r + 1] = -s * (a4 - a3);
else
b[r + 1] = t * (a3 - a4);
ans += b[r + 1] + b[l];
printf("%lld\n", ans);
}
return 0;
}
