#include <bits/stdc++.h>
using namespace std;
#define oo 1e9
#define fi first
#define se second
#define sp(iiii) setprecision(iiii)
#define IO ios_base::sync_with_stdio(false); cin.tie(0)
#define ms(aaaa,xxxx) memset(aaaa,xxxx,sizeof(aaaa))
#define cntbit(xxxx) __builtin_popcount(xxxx)
#define getbit(xxxx,aaaa) ((xxxx>>(aaaa-1))&1)
#define _cos(xxxx) cos(xxxx*acos(-1)/180)
#define _sin(xxxx) sin(xxxx*acos(-1)/180)
#define _tan(xxxx) tan(xxxx*acos(-1)/180)
#define PE cout<<fixed
typedef long double ld;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<pair<int,int>,int> piii;
typedef pair<long long,long long> pll;
typedef pair<pair<long long,long long>,long long> plll;
const ld pi=acos(-1);
ll n,q,s,t,i,a[500009],b[500009],res,l,r,x,tmp1,tmp2;
int main(){
IO;
cin>>n>>q>>s>>t;
for (i=0;i<=n;i++) {
cin>>a[i];
}
for (i=1;i<=n;i++) {
b[i]=a[i]-a[i-1];
}
for (i=1;i<=n;i++) {
res+=(b[i]>0)?(-b[i]*s):(-b[i]*t);
}
//cout<<res<<'\n';
for (i=1;i<=q;i++) {
cin>>l>>r>>x;
tmp1=b[l]+x;
tmp2=b[r+1]-x;
res+=(b[l]>0)?(b[l]*s):(b[l]*t);
res+=(tmp1>0)?(-tmp1*s):(-tmp1*t);
if (r!=n) {
res+=(b[r+1]>0)?(b[r+1]*s):(b[r+1]*t);
res+=(tmp2>0)?(-tmp2*s):(-tmp2*t);
}
b[l]=tmp1;
b[r+1]=tmp2;
cout<<res<<'\n';
}
}
