#define _CRT_SECURE_NO_WARNINGS
#ifdef KEK
#define FILE_IN "input.txt"
#define FILE_OUT "output.txt"
#endif
#include <iostream>
#include <cstdlib>
#include <climits>
#include <set>
#include <map>
#include <cstdio>
#include <string>
#include <cstring>
#include <cassert>
#include <vector>
#include <algorithm>
#include <queue>
using namespace std;
typedef long long ll;
void openFiles() {
#ifdef KEK
assert(freopen(FILE_IN, "r", stdin));
assert(freopen(FILE_OUT, "w", stdout));
#endif
}
const int MAXN = 200000 + 10;
ll a[MAXN];
int n, q, s_up, s_down;
ll delta[MAXN];
int sign(ll f) {
return (f >= 0);
}
int main() {
openFiles();
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n >> q >> s_up >> s_down;
n++;
for (int i = 0; i < n; i++) {
cin >> a[i];
}
ll up_cnt = 0, down_cnt = 0;
for (int i = 1; i < n; i++) {
delta[i] = a[i] - a[i - 1];
if (a[i] > a[i - 1]) {
up_cnt += delta[i];
}
else {
down_cnt += -delta[i];
}
}
for (int j = 0; j < q; j++) {
int l, r;
ll x;
cin >> l >> r >> x;
ll left_dist = delta[l];
ll right_dist = delta[r + 1];
delta[l] += x;
delta[r + 1] -= x;
if (sign(delta[l]) == sign(left_dist)) {
if (sign(left_dist) == 1) {
up_cnt += x;
}
else {
down_cnt -= x;
}
}
else {
if (sign(left_dist) == 1) {
up_cnt -= left_dist;
down_cnt += -delta[l];
}
else {
down_cnt -= -left_dist;
up_cnt += delta[l];
}
}
if (r != n - 1) {
if (sign(delta[r + 1]) == sign(right_dist)) {
if (sign(right_dist) == 1) {
up_cnt -= x;
}
else {
down_cnt += x;
}
}
else {
if (sign(right_dist) == 1) {
up_cnt -= right_dist;
down_cnt += -delta[r + 1];
}
else {
down_cnt -= -right_dist;
up_cnt += delta[r + 1];
}
}
}
ll res = down_cnt * s_down - up_cnt * s_up;
cout << res << "\n";
}
return 0;
}
