#include<bits/stdc++.h>
#ifdef LOCAL
#include "Essentials/algo/debug.h"
#else
#define debug(...) 69
#endif
using namespace std;
//#pragma GCC optimize("O3,unroll-loops")
//#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
//https://quera.org/profile/4dykhk
typedef long long ll;
typedef long double ldb;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
const int N = 2e5 + 23;
const int sq = 450;
const ll mod = 1e9+7; // 998244353
const int LOG = 23;
const ll inf = 1e18;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define F first
#define S second
#define pb push_back
#define ms(x,y) memset((x) , (y) , sizeof (x))
#define done return cout<<endl , 0;
#define kill(x) cout<<x<<endl, exit(0);
#define isIn(x,s,e) ((x) >= (s) && (x) <= e)
#define all(x) x.begin(),x.end()
#define sz(x) (int)x.size()
#define pc(x) __builtin_popcount(x)
#define ctz(x) __builtin_ctz(x)
#define MinHeap(x) priority_queue<x, vector<x> , greater<x> >
#define MaxHeap(x) priority_queue<x, vector<x>>
#define lc (v << 1)
#define rc ((v<<1) |1)
#define int ll
ll pw(ll a, ll b, ll md = mod){ll res = 1; while(b){if(b&1){res=(a*res)%md;}a=(a*a)%md;b>>=1;}return(res);}
int n;
int a[N];
int t[N<<2];
void build(int v=1,int tl=0,int tr=n+1) {
if(tr-tl ==1) {
t[v] = a[tl];
return;
}
int mid=(tl+tr)/2;
build(lc,tl,mid);
build(rc,mid,tr);
}
void shift(int v) {
if(t[v] == 0) return;
t[lc] += t[v];
t[rc] += t[v];
t[v] = 0;
}
void upd(int l,int r,int x,int v =1,int tl = 0 ,int tr = n+1) {
if(l > r) return;
if(l == tl && r == tr-1) {
t[v] += x;
return;
}
shift(v);
int mid=(tl+tr)/2;
upd(l,min(mid-1,r),x,lc,tl,mid);
upd(max(l,mid),r,x,rc,mid,tr);
}
int get(int pos,int v=1,int tl = 0, int tr =n+1) {
if(tr-tl ==1) return t[v];
shift(v);
int mid=(tl+tr)/2;
if(pos<mid)
return get(pos,lc,tl,mid);
else
return get(pos,rc,mid,tr);
}
/*void print(__int128_t x) {
string s;
while(x > 0) {
s.pb(x%10 + '0');
x/=10;
}
if(sz(s) ==0) s.pb('0');
reverse(all(s));
cout<<s<<'\n';
}*/
int q,s,l;
int val(int i) {
if(i == n) return 0;
if(get(i) < get(i+1)) {
return -(get(i+1)-get(i))*s;
} else {
return (get(i) - get(i+1))*l;
}
}
int32_t main() {
cin.tie(nullptr)->sync_with_stdio(false);
cin>>n>>q>>s>>l;
for(int i = 0; i <= n ;i ++) cin>>a[i];
build();
int sum =0;
for(int i = 0 ; i < n; i ++) {
if(a[i] < a[i+1]) {
sum -= (a[i+1]-a[i])*s;
} else {
sum += (a[i] - a[i+1])*l;
}
}
debug(sum);
while(q--) {
int l,r,x; cin>>l>>r>>x;
sum -= val(l-1);
sum -= val(r);
debug(val(l-1),val(r));
upd(l,r,x);
sum += val(l-1);
sum += val(r);
cout<<sum << '\n';
}
done;
}
