#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
using namespace std;
#define int ll
#define FOR(i,s,e) for(ll i = s; i <= (ll)e; ++i)
#define DEC(i,s,e) for(ll i = s; i >= (ll)e; --i)
#define IAMSPEED ios_base::sync_with_stdio(false); cin.tie(0);
#define db(x) cerr << #x << "=" << x << "\n"
#define db2(x, y) cerr << #x << "=" << x << " , " << #y << "=" << y << "\n"
#define db3(a,b,c) cerr<<#a<<"="<<a<<","<<#b<<"="<<b<<","<<#c<<"="<<c<<"\n"
#define dbv(v) cerr << #v << ":"; for (auto ite : v) cerr << ite << ' '; cerr <<"\n"
#define dbvp(v) cerr << #v << ":"; for (auto ite : v) cerr << "{" << ite.f << ',' << ite.s << "} "; cerr << "\n"
#define dba(a,ss,ee) cerr << #a << ":"; FOR(ite,ss,ee) cerr << a[ite] << ' '; cerr << "\n"
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define ll long long
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define f first
#define s second
#define reach cerr << "LINE: " << __LINE__ << "\n";
typedef pair <ll, ll> pi;
typedef tuple<ll,ll,ll> ti3;
string cts(char x) {string t(1,x); return t;}
ll rand(ll a, ll b) { return a + rng() % (b-a+1); }
const int MOD = 1e9 + 7;
const int inf = (int)1e9 + 500;
const long long oo = (ll)1e18 + 500;
template <typename T> void chmax(T& a, T b) { a = max(a, b); }
template <typename T> void chmin(T& a, T b) { a = min(a, b); }
const int MAXN = 2e5+5;
#ifndef LOCAL
#define cerr if(0)cout
#endif
int A[MAXN];
struct node {
int s,e,m,val,lazy;
node *l, *r;
node(int _s, int _e) {
s = _s, e = _e;
m = (s+e)/2;
lazy = 0;
if(s!=e){
l=new node(s,m);
r=new node(m+1,e);
} else {
val=A[s];
}
}
int value(){
if(lazy==0)return val;
val+=lazy;
if(s!=e){
l->lazy+=lazy;
r->lazy+=lazy;
}
lazy=0;
return val;
}
void update(int x, int y, int nval) {
value();
if(s==x&&e==y){
lazy+=nval;
return;
}
if(x>m)r->update(x,y,nval);
else if(y<=m)l->update(x,y,nval);
else l->update(x,m,nval),r->update(m+1,y,nval);
}
int get(int x) {
value();
if(s==e)return val;
if(x>m)return r->get(x);
else return l->get(x);
}
} *seg;
ll n,Q,s,t;
ll calc(ll now, ll last) {
ll res = 0;
if(last<now){
res-=s*(now-last);
} else {
res+=t*(last-now);
}
return res;
}
int32_t main()
{
IAMSPEED
cin>>n>>Q>>s>>t;
FOR(i,0,n)cin>>A[i];
seg=new node(0,n);
ll ans = 0;
FOR(i,1,n){
ll now = A[i], last = A[i-1];
ans+=calc(now,last);
}
//db(ans);
while(Q--){
int l,r,nval; cin >> l >> r >> nval;
ans-=calc(seg->get(l),seg->get(l-1));
if(r!=n){
ans-=calc(seg->get(r+1),seg->get(r));
}
ans+=calc(nval+seg->get(l),seg->get(l-1));
if(r!=n){
ans+=calc(seg->get(r+1),seg->get(r)+nval);
}
seg->update(l,r,nval);
cout << ans << '\n';
}
}
/* DEBUG
** Array bounds
** Overflow
** Edge cases
** do something
** write stuff down
*/
