#include <bits/stdc++.h>
#define int long long
//#define double long double
#define Nanase_Kurumi_aka_menhera_chan_is_mine ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define pb push_back
#define pi pair<int, int>
#define ALL(i) i.begin(),i.end()
#define gcd(i,j) __gcd(i,j)
#define fi first
#define se second
#define eps 0.00000001
#define ist insert
#define DNE nullptr
//#pragma GCC optimize("Ofast,unroll-loops,no-stack-protector,fast-math")
//#pragma GCC optimize("O2")
int max(int x,int y){return x>=y?x:y;}
int min(int x,int y){return x>=y?y:x;}
using namespace std;
typedef int ll;
const int N=200005;
const int M=1000005;
const int MOD=1000000007;//998244353;
const int INF=1000000000000000000;//2147483647;
int n,q,S,T;
int a[N],b[N];
/*int calc1(int x,int y){
if (x<0&&y>0)
return abs(x)*T+y*S;
else if (y<0)
return abs(y-x)*T;
else return (y-x)*S;
}
int calc2(int x,int y){
if (y<0&&x>0)
return abs(y)*T+x*S;
else if (x<0)
return abs(x-y)*T;
else
}*/
inline void sol(){
cin >>n>>q>>S>>T;
for (int i=0;i<=n;i++)
cin >>a[i];
for (int i=1;i<=n;i++)
b[i]=a[i]-a[i-1];
int res=0;
for (int i=1;i<=n;i++)
if (a[i]>a[i-1])
res+=(a[i]-a[i-1])*S;
else res-=(a[i-1]-a[i])*T;
for (int i=0,l,r,x;i<q;i++){
cin >>l>>r>>x;
if (b[l]<0) res-=b[l]*T;
else res-=b[l]*S;
if (r!=n){
if (b[r+1]<0) res-=b[r+1]*T;
else res-=b[r+1]*S;
}
b[l]+=x;
if (b[l]<0) res+=b[l]*T;
else res+=b[l]*S;
b[r+1]-=x;
if (r!=n){
if (b[r+1]<0) res+=b[r+1]*T;
else res+=b[r+1]*S;
}
//for (int j=1;j<=n;j++) cout <<b[j]<<' ';
cout <<-res<<'\n';
}
}
signed main(){
Nanase_Kurumi_aka_menhera_chan_is_mine
int _=1;
//cin >>_;
while (_--) sol();
return 0;
}
