#include <bits/stdc++.h>
using namespace std;
#define int long long
const int maxn = 2e5;
int n, q, s, t, sumS = 0, sumT = 0;
int bit[maxn + 5];
int ls(int x) { return x & (-x); }
void upd(int x, int val)
{
for (int i = x; i <= maxn; i += ls(i))
bit[i] += val;
}
int get(int x)
{
int res = 0;
for (int i = x; i > 0; i -= ls(i))
res += bit[i];
return res;
}
int get(int l, int r)
{
return get(r) - get(l - 1);
}
void updSum(int idx, int type)
{
if (bit[idx] > 0)
sumS += bit[idx] * type;
else
sumT -= bit[idx] * type;
}
signed main()
{
ios_base ::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
cin >> n >> q >> s >> t;
int bfr = 0, cur = 0;
for (int i = 0; i <= n; i++)
{
cin >> cur;
if (i == 0)
{
bfr = cur;
continue;
}
bit[i] = cur - bfr;
// cout << ": " << bit[i] << '\n';
updSum(i, 1);
bfr = cur;
}
while (q--)
{
// cout << ":: " << sumS << ' ' << sumT << '\n';
int l, r, x;
cin >> l >> r >> x;
updSum(l, -1);
if(r + 1 <= n)
updSum(r + 1, -1);
bit[l] += x;
bit[r + 1] -= x;
updSum(l, 1);
if(r + 1 <= n)
updSum(r + 1, 1);
cout << -sumS * s + sumT * t << '\n';
}
}
/*
0 4 1 8
4 -3 7
sumS = 11
sumT = 3
0 6 3 8
6 -3 5
- 6 x 1 + 3 x 2 - 5 x 1 = -5
0 4 3 8
4 -1 5
- 4 x 1 + 1 x 2 - 5 x 1 = -7
0 4 8 13
*/
