#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define sz(x) (int)x.size()
#define ALL(v) v.begin(),v.end()
#define MASK(k) (1LL << (k))
#define BIT(x, i) (((x) >> (i)) & 1)
#define oo (ll)1e18 + 10
#define INF (ll)1e9
#define MOD (ll)(1e9 + 7)
using namespace std;
template<class T1, class T2>
bool maximize(T1 &a, T2 b){if(a < b){a = b; return true;} return false;}
template<class T1, class T2>
bool minimize(T1 &a, T2 b){if(a > b){a = b; return true;} return false;}
template<class T1, class T2>
void add(T1 &a, T2 b){a += b; if(a >= MOD) a -= MOD;}
template<class T1, class T2>
void sub(T1 &a, T2 b){a -= b; if(a < 0) a += MOD;}
template<class T>
void cps(T &v){sort(ALL(v)); v.resize(unique(ALL(v)) - v.begin());}
struct fen{
vector<ll> tree;
int n;
fen(int _n = 0){
n = _n;
tree.resize(n + 3, 0);
}
void upd(int p, ll c){
for(; p <= n; p += p & -p) tree[p] += c;
}
ll get(int p){
ll ans = 0;
for(; p > 0; p -= p & -p) ans += tree[p];
return ans;
}
};
const int maxN = 2e5 + 10;
int N, Q, S, T;
int a[maxN];
void solve(){
cin >> N >> Q >> S >> T;
for(int i = 0; i <= N; i++) cin >> a[i];
ll larger = 0, smaller = 0;
fen bit(N);
for(int i = 1; i <= N; i++){
bit.upd(i, a[i]);
bit.upd(i + 1, -a[i]);
if(a[i] > a[i - 1]) larger += a[i] - a[i - 1];
else smaller += a[i - 1] - a[i];
}
while(Q--){
int l, r, x; cin >> l >> r >> x;
ll val_l = bit.get(l);
ll pre_l = bit.get(l - 1);
if(val_l > pre_l) larger -= val_l - pre_l;
else smaller -= pre_l - val_l;
ll val_r = bit.get(r);
ll nxt_r = bit.get(r + 1);
if(r < N){
if(nxt_r > val_r) larger -= nxt_r - val_r;
else smaller -= val_r - nxt_r;
}
bit.upd(l, x);
bit.upd(r + 1, -x);
val_l = bit.get(l);
pre_l = bit.get(l - 1);
if(val_l > pre_l) larger += val_l - pre_l;
else smaller += pre_l - val_l;
val_r = bit.get(r);
nxt_r = bit.get(r + 1);
if(r < N){
if(nxt_r > val_r) larger += nxt_r - val_r;
else smaller += val_r - nxt_r;
}
cout << -1LL * larger * S + 1LL * smaller * T << '\n';
}
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0);
// freopen("bdbang.inp","r",stdin);
// freopen("bdbang.out","w",stdout);
int t = 1;
// cin >> t;
while(t--)
solve();
return 0;
}
