#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <string>
#include <cmath>
#include <cstdio>
#include <iomanip>
#include <fstream>
#include <cassert>
#include <cstring>
#include <numeric>
#include <ctime>
#include <complex>
#include <bitset>
#include <random>
#include <climits>
#include <stack>
/*#pragma GCC optimize("Ofast")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,sse4.1,sse4.2,popcnt,abm,mmx,avx,avx2,tune=native")*/
using namespace std;
typedef long long ll;
typedef long double ld;
#define int ll
#define double ld
#define loop(i, n) for(int i = 0; i < (int)n; ++i)
#define loop1(i, n) for(int i = 1; i <= (int)n; ++i)
#define F first
#define S second
#define pb push_back
#define pi pair <int, int>
#define all(x) begin(x), end(x)
#define ti tuple <int, int, int>
#define Point Vect
#define no {cout << "No"; return;}
#define yes {cout << "Yes"; return;}
#define mkp make_pair
#define mkt make_tuple
#define cerr if(0) cerr
const int N = 2e5 + 7;
int t[2][4 * N], add[2][4 * N], a[N], w[N];
void build(int v, int l, int r) {
if (l == r) {
t[0][v] = a[l];
t[1][v] = w[l];
return;
}
int m = l + r >> 1;
build(2 * v + 1, l, m);
build(2 * v + 2, m + 1, r);
}
void push(int v, int l, int r) {
if (l != r) {
loop(i, 2) {
add[i][2 * v + 1] += add[i][v];
add[i][2 * v + 2] += add[i][v];
}
}
else {
loop(i, 2) {
t[i][v] += add[i][v];
}
}
add[0][v] = add[1][v] = 0;
}
void change(int v, int l, int r, int L, int R, int val, int f) {
push(v, l, r);
if (l > R || r < L)
return;
if (l >= L && r <= R) {
add[f][v] += val;
push(v, l, r);
return;
}
int m = l + r >> 1;
change(2 * v + 1, l, m, L, R, val, f);
change(2 * v + 2, m + 1, r, L, R, val, f);
}
int ask(int v, int l, int r, int pos) {
push(v, l, r);
if (l == r)
return v;
int m = l + r >> 1;
if (pos <= m)
return ask(2 * v + 1, l, m, pos);
else
return ask(2 * v + 2, m + 1, r, pos);
}
void solve() {
int n, q, u, d;
cin >> n >> q >> u >> d;
++n;
loop(i, n) {
cin >> a[i];
if (i) {
w[i] = w[i - 1];
if (a[i] > a[i - 1])
w[i] -= (a[i] - a[i - 1]) * u;
else
w[i] += (a[i - 1] - a[i]) * d;
}
}
build(0, 0, n);
loop(i, q) {
int l, r, x;
cin >> l >> r >> x;
int wasl = t[0][ask(0, 0, n, l)], wasr = t[0][ask(0, 0, n, r)];
change(0, 0, n, l, r, x, 0);
int curl = t[0][ask(0, 0, n, l)], curr = t[0][ask(0, 0, n, r)];
int L = t[0][ask(0, 0, n, l - 1)], R = t[0][ask(0, 0, n, r + 1)];
change(0, 0, n, l, n, (wasl - L) * (wasl > L ? u : d) + (L - curl) * (curl > L ? u : d), 1);
change(0, 0, n, r + 1, n, (R - wasr) * (R > wasr ? u : d) + (curr - R) * (R > curr ? u : d), 1);
cout << t[1][ask(0, 0, n, n - 1)] << "\n";
}
}
signed main() {
//freopen("dream.in", "r", stdin);
//freopen("dream.out", "w", stdout);
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
//int t; cin >> t; loop(i, t)
solve();
return 0;
}
