#include "bits/stdc++.h"
#define MAXN 200009
#define INF 1000000007
#define mp(x,y) make_pair(x,y)
#define all(v) v.begin(),v.end()
#define pb(x) push_back(x)
#define wr cout<<"----------------"<<endl;
#define ppb() pop_back()
#define tr(ii,c) for(__typeof((c).begin()) ii=(c).begin();ii!=(c).end();ii++)
#define ff first
#define ss second
#define my_little_dodge 46
#define debug(x) cerr<< #x <<" = "<< x<<endl;
using namespace std;
typedef long long ll;
typedef pair<int,int> PII;
template<class T>bool umin(T& a,T b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool umax(T& a,T b){if(a<b){a=b;return 1;}return 0;}
ll s[MAXN<<2],ans;
int arr[MAXN],n,q,sa,t;
void inc(int l,int r,int v,int nd=1,int x=1,int y=n){
if(l>y or x>r)return;
if(l<=x and y<=r){s[nd]+=v;return;}
int mid=(x+y)>>1;
inc(l,r,v,nd<<1,x,mid);inc(l,r,v,nd<<1|1,mid+1,y);
}
ll get(int p,int nd=1,int x=1,int y=n){
if(!p)return 0LL;
if(x==y)return s[nd]+arr[x];
int mid=(x+y)>>1;
if(p<=mid)return s[nd]+get(p,nd<<1,x,mid);
return s[nd]+get(p,nd<<1|1,mid+1,y);
}
ll cost(int p){
ll a=get(p),b=get(p+1);
if(a<b)
return sa*(a-b);
return t*(a-b);
}
int main(){
//freopen("dreaming.in", "r", stdin);
scanf("%d%d%d%d",&n,&q,&sa,&t);
for(int i=0;i<=n;i++)scanf("%d",arr+i);
for(int i=0;i<n;i++)ans+=cost(i);
while(q--){
int l,r,x;
scanf("%d%d%d",&l,&r,&x);
ans-=cost(l-1);if(r<n)ans-=cost(r);
inc(l,r,x);
ans+=cost(l-1);if(r<n)ans+=cost(r);
printf("%lld\n",ans);
}
return 0;
}
