#include <algorithm>
#include <bitset>
#include <cassert>
#include <chrono>
#include <cstring>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <vector>
using namespace std;
// BEGIN NO SAD
#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define trav(a, x) for(auto& a : x)
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x).size()
typedef vector<int> vi;
// END NO SAD
typedef long long ll;
typedef pair<int, int> pii;
const int RAGETREE_SZ = 1 << 18;
ll bit[RAGETREE_SZ];
void upd(int idx, ll val) {
idx += 2;
while(idx < RAGETREE_SZ) {
bit[idx] += val;
idx += idx & -idx;
}
}
ll qry(int idx) {
idx += 2;
ll ret = 0;
while(idx) {
ret += bit[idx];
idx -= idx & -idx;
}
return ret;
}
void solve() {
int n, q;
ll s, t;
ll pos = 0;
ll neg = 0;
cin >> n >> q >> s >> t;
{
ll last = 0;
for(int i = 0; i <= n; i++) {
ll curr;
cin >> curr;
upd(i, curr - last);
last = curr;
}
}
for(int i = 1; i <= n; i++) {
ll delta = qry(i) - qry(i-1);
if(delta > 0) pos += delta;
else neg -= delta;
}
while(q--) {
int lhs, rhs, k;
cin >> lhs >> rhs >> k;
ll delta;
delta = qry(lhs) - qry(lhs-1);
if(delta > 0) pos -= delta;
else neg += delta;
if(rhs < n) {
delta = qry(rhs+1) - qry(rhs);
if(delta > 0) pos -= delta;
else neg += delta;
}
upd(lhs, k);
upd(rhs+1, -k);
delta = qry(lhs) - qry(lhs-1);
if(delta > 0) pos += delta;
else neg -= delta;
if(rhs < n) {
delta = qry(rhs+1) - qry(rhs);
if(delta > 0) pos += delta;
else neg -= delta;
}
cout << t*neg - s*pos << "\n";
}
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL); cout.tie(NULL);
solve();
}
