#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define int long long
struct node
{
int value, lazy;
node(int v = 0LL)
{
value = v;
lazy = 0LL;
}
};
node tree[(int)1e6]; int l;
void update(int v, int s, int e, int k)
{
tree[v].lazy += k;
tree[v].value += (e - s + 1) * k;
}
void push(int v, int s, int e)
{
if (tree[v].lazy)
{
int middle = (s + e) / 2;
update(2 * v, s, middle, tree[v].lazy);
update(2 * v + 1, middle + 1, e, tree[v].lazy);
tree[v].lazy = 0LL;
}
}
void increase(int node, int v, int x, int y, int s, int e)
{
if (x > e || y < s) return;
if (s >= x && e <= y)
{
update(node, s, e, v);
return;
}
push(node, s, e);
int middle = (s + e) / 2;
increase(node * 2, v, x, y, s, middle);
increase(node * 2 + 1, v, x, y, middle + 1, e);
tree[node].value = tree[node * 2].value
+ tree[node * 2 + 1].value;
}
void increase(int x, int y, int v) { increase(1, v, x, y, 1, l); }
int sum(int node, int x, int y, int s, int e)
{
if (x > e || y < s) return 0LL;
if (s >= x && e <= y)
return tree[node].value;
push(node, s, e);
int middle = (s + e) / 2;
return sum(node * 2, x, y, s, middle) +
sum(node * 2 + 1, x, y, middle + 1, e);
}
int query(int x) { return sum(1, x, x, 1, l); }
void Segment_tree(int n)
{
for (l = 1; l < n; l = (l << 1));
}
int32_t main()
{
ll n,q,s,t;
cin>>n>>q>>s>>t;
ll cad[n+1];
Segment_tree (n+2);
for(int i=0LL; i<n+1; i++)
{
cin>>cad[i];
}
ll sol=0LL;
for(int i=1; i<=n; i++)
{
sol-=s*max(cad[i]-cad[i-1],0LL);
sol+=t*max(cad[i-1]-cad[i],0LL);
increase(i+1,i+1,cad[i]);
}
while(q--)
{
ll a,b,c;
cin>>a>>b>>c;
a++;
b++;
ll t1=query(a),t2=query(a-1);
sol+=s*max(t1-t2,0LL);
sol-=t*max(t2-t1,0LL);
if(b!=n+1){
ll t3=query(b+1), t4=query(b);
sol+=s*max(t3-t4,0LL);
sol-=t*max(t4-t3,0LL);}
increase(a,b,c);
t1=query(a),t2=query(a-1);
sol-=s*max(t1-t2,0LL);
sol+=t*max(t2-t1,0LL);
if(b!=n+1){
ll t3=query(b+1), t4=query(b);
sol-=s*max(t3-t4,0LL);
sol+=t*max(t4-t3,0LL);}
cout<<sol<<"\n";
}
}
