#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
#define ll long long
#define int long long
const int nmax = 2e5 + 5;
const int lg = 18;
const int base = 311;
const int M = 5e6;
const ll oo = 1e9;
const int mod = 987654321;
#define fi first
#define se second
#define endl "\n"
#define pii pair<ll, int>
using namespace std;
int n, q, S, T, a[nmax];
int tree[nmax << 2], lz[nmax << 2];
void build(int id, int l, int r){
if(l == r){
tree[id] = a[l];
return;
}
int mid = r + l >> 1;
build(id << 1, l, mid);
build(id << 1 | 1, mid + 1, r);
}
void fix(int id, int val){
lz[id] += val;
tree[id] += val;
}
void down(int id){
fix(id << 1, lz[id]);
fix(id << 1 | 1, lz[id]);
lz[id] = 0;
}
void update(int id, int l, int r, int u, int v, int x){
if(l > v || r < u) return;
if(l >= u && r <= v){
return fix(id, x);
}
down(id);
int mid = r + l >> 1;
update(id << 1, l, mid, u, v, x);
update(id << 1 | 1, mid + 1, r, u, v, x);
}
#define update(l, r, x) update(1, 0, n, l, r, x)
int get(int id, int l, int r, int u){
if(l == r) return tree[id];
down(id);
int mid = r + l >> 1;
if(u <= mid) return get(id << 1, l, mid, u);
return get(id << 1 | 1, mid + 1, r, u);
}
#define get(u) get(1, 0, n, u)
main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL), cout.tie(NULL);
// freopen("code.inp", "r", stdin);
// freopen("code.out", "w", stdout);
cin >> n >> q >> S >> T;
for(int i = 0; i <= n; ++i) cin >> a[i];
build(1, 0, n);
int c1 = 0, c2 = 0;
for(int i = 0; i < n; ++i){
if(a[i] < a[i + 1]) c1 += abs(a[i + 1] - a[i]);
else c2 += abs(a[i + 1] - a[i]);
}
// cout << c1 << ' ' << c2 << endl;
while(q--){
int l, r, x;
cin >> l >> r >> x;
if(get(l - 1) < get(l)) c1 -= abs(get(l - 1) - get(l));
else c2 -= abs(get(l - 1) - get(l));
if(r < n){
if(get(r) < get(r + 1)) c1 -= abs(get(r) - get(r + 1));
else c2 -= abs(get(r) - get(r + 1));
}
update(l, r, x);
if(get(l - 1) < get(l)) c1 += abs(get(l - 1) - get(l));
else c2 += abs(get(l - 1) - get(l));
if(r < n){
if(get(r) < get(r + 1)) c1 += abs(get(r) - get(r + 1));
else c2 += abs(get(r) - get(r + 1));
}
// for(int i = 0; i <= n; ++i) cout << get(i) << ' ';
// cout << endl;
cout << -S *c1 + T * c2 << endl;
}
}
/*
4
-7 5
6 -1
-10 10
-3 6
*/
