# include <bits/stdc++.h>
#define f first
#define s second
#define pb push_back
using namespace std;
const int N=3e5+5;
long long n,m,s,t,a[N],pr[N],le,ri,ad,prl,l,r,nxr,tree[2*N],tree2[2*N],xx,xx1;
void update1(long long idx, long long val) {
for (long long i=idx; i<=N; i+=i&(-i)) {
tree[i]+=val;
}
}
long long getans1(long long idx) {
long long pas=0;
for (long long i=idx; i>0; i-=i&(-i)) {
pas+=tree[i];
}
return pas;
}
void update2(long long idx, long long val) {
for (long long i=idx; i<=N; i+=i&(-i)) {
tree2[i]+=val;
}
}
long long getans2(long long idx) {
long long pas=0;
for (long long i=idx; i>0; i-=i&(-i)) {
pas+=tree2[i];
}
return pas;
}
long long go(long long a, long long b) {
if (a<b) return -abs(a-b)*s;
else return abs(a-b)*t;
}
int main() {
std::ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0);
cin>>n>>m>>s>>t;
for (int i=1; i<=n+1; i++) {
cin>>a[i];
update1(i,a[i]);
update1(i+1, -a[i]);
}
//cout<<getans1(1)<<endl<<endl;
pr[1]=0;
for (int i=2; i<=n+1; i++) {
long long ww=go(a[i-1],a[i]);
// cout<<i<<" "<<ww<<endl;
pr[i]=pr[i-1]+ww;
update2(i,ww);
// update2(i+1, -ww);
}
// cout<<getans2(n+1)<<endl<<endl<<endl;
for (int i=1; i<=m; i++) {
cin>>le>>ri>>ad;
le++;
ri++;
l=getans1(le);
prl=getans1(le-1);
xx=go(prl,l);
xx1=go(prl,l+ad);
//cout<<prl<<" "<<l<<" "<<xx<<" "<<xx1<<endl;
update2(le,xx1-xx);
//cout<<getans2(n+1)<<endl<<endl;
//update2(r+1, xx-xx1);
r=getans1(ri);
nxr=getans1(ri+1);
xx=go(r,nxr);
xx1=go(r+ad,nxr);//cout<<r<<" "<<nxr<<" "<<xx<<" "<<xx1<<endl;
update2(ri+1, xx1-xx);
cout<<getans2(n+1)<<endl;
update1(le,ad);
update1(ri+1, -ad);
}
}
