#pragma GCC optimization "Ofast"
#pragma GCC optimization "unroll-loop"
#pragma GCC target ("avx2")
#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define fs first
#define sc second
using namespace std;
const ll N = 2e5 + 9;
const ll inf = 1e18 + 7;
const ll Log2 = 20;
typedef pair<ll,ll> LL;
ll n,Q,s,t,a[N],temp[N];
ll st[2][4*N],lazy[2][4*N],L,R,x;
void Pass(ll cond,ll id){
ll t = lazy[cond][id]; lazy[cond][id] = 0;
st[cond][id*2] += t; st[cond][id*2 + 1] += t;
lazy[cond][id*2] += t; lazy[cond][id*2 + 1] += t;
}
void upd(ll cond,ll id,ll l,ll r,ll u,ll v,ll val){
if (v < l||r < u) return;
if (u <= l&&r <= v){
st[cond][id] += val; lazy[cond][id] += val;
return;
}
ll mid = (l + r)/2; Pass(cond,id);
upd(cond,id*2,l,mid,u,v,val); upd(cond,id*2 + 1,mid + 1,r,u,v,val);
st[cond][id] = max(st[cond][id*2],st[cond][id*2 + 1]);
}
ll Get(ll cond,ll id,ll l,ll r,ll u){
if (!u) return 0;
if (u < l||r < u) return -inf;
if (l == r) return st[cond][id];
ll mid = (l + r)/2; Pass(cond,id);
return max(Get(cond,id*2,l,mid,u),Get(cond,id*2 + 1,mid + 1,r,u));
}
/// 0 for a 1 for temp
ll Get_temp(ll a,ll b){
if (a < b) return (a - b)*s;
return (a - b)*t;
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
#define task "tst"
if (fopen(task".inp","r")){
freopen(task".inp","r",stdin);
//freopen(task".out","w",stdout);
}
cin>>n>>Q>>s>>t;
for (ll i = 0;i <= n;i++) cin>>a[i];
for (ll i = 0;i < n;i++){
temp[i + 1] = temp[i];
if (a[i] < a[i + 1]) temp[i + 1] -= (a[i + 1] - a[i])*s;
else temp[i + 1] += (a[i] - a[i + 1])*t;
upd(0,1,1,n,i + 1,i + 1,a[i + 1]); upd(1,1,1,n,i + 1,i + 1,temp[i + 1]);
}
//cout<<temp[1]; return 0;
//for (ll i = 1;i <= n;i++) cout<<Get(1,1,1,n,i)<<" "; return 0;
while(Q--){
cin>>L>>R>>x;
ll prv0 = Get(0,1,1,n,L),prv1 = Get(1,1,1,n,L);
ll new_temp = prv0 + x; new_temp = Get(1,1,1,n,L - 1) + Get_temp(Get(0,1,1,n,L - 1),new_temp);
ll diff = new_temp - prv1; //cout<<diff; return 0;
upd(1,1,1,n,L,R,diff); upd(0,1,1,n,L,R,x);
ll diff2 = Get(1,1,1,n,R) + Get_temp(Get(0,1,1,n,R),Get(0,1,1,n,R + 1)) - Get(1,1,1,n,R + 1);
//cout<<diff2; exit(0);
//upd(1,1,1,n,R + 1,n,diff2);
//for (ll i = 1;i <= n;i++) cout<<Get(1,1,1,n,i)<<" "; return 0;
cout<<Get(1,1,1,n,n)<<"\n";
}
}
