#include <iostream>
#include <vector>
#include <cassert>
#include <cmath>
using namespace std;
using ll = long long;
#define MIN(a, b) (((a) < (b)) ? (a) : (b))
#define MAX(a, b) (((a) < (b)) ? (b) : (a))
int const nmax = 200000;
ll v[5 + nmax], dif[1 + nmax];
int s, t;
ll getvalue(int pos){
if(0 < dif[pos])
return dif[pos] * t;
else
return dif[pos] * s;
}
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
int n, q;
cin >> n >> q >> s >> t;
for(int i = 0;i <= n; i++)
cin >> v[i];
for(int i = 0; i < n; i++)
dif[i] = v[i] - v[i + 1];
ll result = 0;
for(int i = 0; i < n; i++)
result += getvalue(i);
for(int i = 1; i <= q; i++){
int x, y, val;
cin >> x >> y >> val;
result -= getvalue(x - 1);
if(y < n)
result -= getvalue(y);
dif[x - 1] -= val;
if(y < n)
dif[y] += val;
result += getvalue(x - 1);
if(y < n)
result += getvalue(y);
cout << result << '\n';
}
return 0;
}
