#include <bits/stdc++.h>
#define int long long
using namespace std;
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
int n, q, s, t;
cin >> n >> q >> s >> t;
int diff[n+2] = {0}, temp[n+1];
int sum = 0;
for(int loop = 0; loop < n+1; ++loop) {
cin >> temp[loop];
}
for(int loop = 1; loop < n+1; ++loop) {
diff[loop] = temp[loop] - temp[loop-1];
if(diff[loop] > 0) {
sum -= diff[loop] * s;
}
else {
sum -= diff[loop] * t;
}
}
for(int loop = 0; loop < q; ++loop) {
int deb, fin, change;
cin >> deb >> fin >> change;
fin++;
if(diff[deb] > 0) {
sum += diff[deb] * s;
}
else {
sum += diff[deb] * t;
}
diff[deb] += change;
if(diff[deb] > 0) {
sum -= diff[deb] * s;
}
else {
sum -= diff[deb] * t;
}
if(fin <= n) {
if(diff[fin] > 0) {
sum += diff[fin] * s;
}
else {
sum += diff[fin] * t;
}
diff[fin] -= change;
if(diff[fin] > 0) {
sum -= diff[fin] * s;
}
else {
sum -= diff[fin] * t;
}
}
cout << sum << '\n';
}
}
