#include<bits/stdc++.h>
#define ll long long
using namespace std;
const ll maxn = 2e5+3;
struct segtree{
ll tree[maxn*4], lazy[maxn*4];
void reset(){
memset(tree, 0, sizeof(tree));
memset(lazy, 0, sizeof(lazy));
}
void down(ll u){
ll t = lazy[u];
tree[u*2]+=t;
tree[u*2+1]+=t;
lazy[u*2]+=t;
lazy[u*2+1]+=t;
lazy[u]=0;
}
void upd(ll id, ll l, ll r, ll u, ll v, ll val){
if(l>r) return ;
if(r<u||v<l) return ;
if(u<=l && v>=r){
tree[id]+=val;
lazy[id]+=val;
return ;
}
down(id);
ll mid = (l+r)>>1;
upd(id*2, l, mid, u, v, val);
upd(id*2+1, mid+1, r, u, v, val);
tree[id]=tree[id*2]+tree[id*2+1];
}
ll get(ll id, ll l, ll r, ll u){
if(u<l||r<u) return 0;
if(l==r) return tree[id];
down(id);
ll mid = (l+r)>>1;
return get(id*2, l, mid, u) + get(id*2+1, mid+1, r, u);
}
} tree;
ll n, q, s, t, x, sum, p, l, r, l1, l2, r1, r2, pl1, pl2, pr1, pr2;
int main(){
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> q >> s >> t;
for(ll i = 0; i <= n; i++){
cin >> x;
if(i==0) continue;
if(p<x) sum -= (x-p)*s;
else sum += (p-x)*t;
tree.upd(1, 1, n, i, i, x);
p=x;
}
while(q--){
cin >> l >> r >> x;
// cout << l << " " << r << "\n";
if(l==1) pl1=0;
else pl1 = tree.get(1, 1, n, l-1);
pl2 = tree.get(1, 1, n, l);
pr1 = tree.get(1, 1, n, r);
if(r==n) pr2 = pr1;
else pr2 = tree.get(1, 1, n, r+1);
// cout << pl1 << " " << pl2 << " " << pr1 << " " << pr2 << "\n";
tree.upd(1, 1, n, l, r, x);
if(l==1) l1=0;
else l1 = tree.get(1, 1, n, l-1);
l2 = tree.get(1, 1, n, l);
r1 = tree.get(1, 1, n, r);
if(r==n) r2 = r1;
else r2 = tree.get(1, 1, n, r+1);
// cout << l1 << " " << l2 << " " << r1 << " " << r2 << "\n";
if(pl1 < pl2){
if(l1 < l2) sum += ((pl2 - pl1) - (l2 - l1))*s;
else{
sum += (pl2 - pl1)*s;
sum += (l1-l2)*t;
}
}
else{
if(l1 > l2){
sum+=((l1-l2) - (pl1-pl2))*t;
}
else{
sum -= (pl1-pl2)*t;
sum -= (l2 - l1)*s;
}
}
// cout << sum << "\n";
if(pr1 < pr2){
if(r1 < r2) sum += ((pr2 - pr1) - (r2 - r1))*s;
else{
sum += (pr2 - pr1)*s;
sum += (r1-r2)*t;
}
}
else{
if(r1 > r2){
sum+=((r1-r2) - (pr1-pr2))*t;
}
else{
sum -= (pr1-pr2)*t;
sum -= (r2 - r1)*s;
}
}
cout << sum << "\n";
}
return 0;
}
