#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define fi first
#define se second
#define for1(i,j,k) for(int i=j;i<=k;i++)
#define for2(i,j,k) for(int i=j;i>=k;i--)
#define for3(i,j,k,l) for(int i=j;i<=k;i+=l)
#define bit(n,i) ((n>>i)&1)
#define all(x) x.begin(),x.end()
#define int long long
typedef long long ll;
typedef pair<int,int> pii;
typedef double ld;
typedef pair<ld,ld> pdd;
typedef pair<ll,ll> pll;
const ll maxn=3e5+5;
const ll offset=2e5;
const ll inf=1e18;
const int base=350;
const ll mod=998244353;
int n,q,s,t,res,a[maxn],b[maxn];
int f(int u)
{
if (u<0) return u*s;
else return u*t;
}
void sol()
{
cin >> n >> q >> s >> t;
for1(i,0,n) cin >> b[i];
for1(i,1,n)
{
a[i]=b[i-1]-b[i];
res+=f(a[i]);
}
for1(i,1,q)
{
int l,r,x; cin >> l>> r>> x;
res-=f(a[l]);
a[l]-=x;
res+=f(a[l]);
if (r!=n)
{
res-=f(a[r+1]);
a[r+1]+=x;
res+=f(a[r+1]);
}
cout << res<<'\n';
}
}
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
// freopen("1017G.inp","r",stdin);
// freopen("1017G.out","w",stdout);
int t=1;//cin >> t;
while (t--) {
sol();
}
}
/*
4 12
1 2 3
1 3
2 3
2 1
1 2
1 2
1 4
1 1
1 1
2 4
2 3
1 1
3 4
*/
