#include <bits/stdc++.h>
#define FOR(i,x,n) for(int i=x; i<n; i++)
#define F0R(i,n) FOR(i,0,n)
#define ROF(i,x,n) for(int i=n-1; i>=x; i--)
#define R0F(i,n) ROF(i,0,n)
#define WTF cout << "WTF" << endl
#define IOS ios::sync_with_stdio(false); cin.tie(0)
#define F first
#define S second
#define pb push_back
#define ALL(x) x.begin(), x.end()
#define RALL(x) x.rbegin(), x.rend()
using namespace std;
typedef long long LL;
typedef pair<int, int> PII;
typedef pair<LL, LL> PLL;
typedef vector<int> VI;
typedef vector<LL> VLL;
typedef vector<PII> VPII;
typedef vector<PLL> VPLL;
const int N = 2e5 + 7;
const int ALPHA = 27;
const int INF = 1e9 + 7;
const int MOD = 1e9 + 7;
const int LOG = 22;
#define lc now << 1
#define rc now << 1 | 1
LL n, q, s, t;
LL ns[N], tree[N << 2];
#define endl '\n'
LL build(int now = 1, int ls = 0, int rs = n - 1) {
if (ls == rs) return tree[now] = ns[ls] * (ns[ls] < 0 ? -t : -s);
int mid = (ls + rs) >> 1;
return tree[now] = build(lc, ls, mid) + build(rc, mid + 1, rs);
}
void change(int id, int now = 1, int ls = 0, int rs = n - 1) {
if (ls == rs) {
tree[now] = ns[ls] * (ns[ls] < 0 ? -t : -s);
return;
}
int mid = (ls + rs) >> 1;
if (id <= mid) change(id, lc, ls, mid);
else change(id, rc, mid + 1, rs);
tree[now] = tree[lc] + tree[rc];
return;
}
int main() {
IOS;
cin >> n >> q >> s >> t;
F0R(i, n + 1) cin >> ns[i];
F0R(i, n) ns[i] = ns[i + 1] - ns[i];
build();
LL lo, hi, v;
while(q--) {
cin >> lo >> hi >> v;
lo--;
ns[lo] += v;
if (hi < n) ns[hi] -= v;
change(lo);
if (hi < n) change(hi);
cout << tree[1] << endl;
}
return 0;
}
