///TRAN THAI BAO :3
#include <iostream>
#include <cstdio>
using namespace std;
#define maxN 200007
int n, q;
long long s, t;
long long a[maxN];
long long curAns = 0;
struct SEG
{
long long st[maxN*4];
long long lazy[maxN*4] = {0};
void build(int id, int l, int r)
{
if(l == r)
{
st[id] = a[l];
return;
}
int mid = (l+r)/2;
build(id*2, l, mid);
build(id*2+1, mid+1, r);
st[id] = st[id*2] + st[id*2+1];
}
void fix(int id, int l, int r)
{
if(lazy[id] == 0)
return;
st[id] += lazy[id]*(r-l+1);
if(l != r)
{
lazy[id*2] += lazy[id];
lazy[id*2+1] += lazy[id];
}
lazy[id] = 0;
}
void update(int id, int l, int r, int u, int v, long long val)
{
fix(id, l, r);
if(l > v || u > r)
return;
if(u <= l && r <= v)
{
lazy[id] += val;
fix(id, l, r);
return;
}
int mid = (l+r)/2;
update(id*2, l, mid, u, v, val);
update(id*2+1, mid+1, r, u, v, val);
st[id] = st[id*2] + st[id*2+1];
}
long long query(int id, int l, int r, int u, int v)
{
fix(id, l, r);
if(l > v || u > r)
return 0;
if(u <= l && r <= v)
return st[id];
int mid = (l+r)/2;
return query(id*2, l, mid, u, v) + query(id*2+1, mid+1, r, u, v);
}
};
SEG seg;
long long getVal(long long pre, long long nxt)
{
long long ans;
if(pre < nxt)
ans = -s*(nxt - pre);
else ans = t*(pre - nxt);
return ans;
}
void readData()
{
cin >> n >> q >> s >> t;
n++;
for(int i = 1; i <= n; i++)
cin >> a[i];
for(int i = 2; i <= n; i++)
curAns += getVal(a[i-1], a[i]);
}
void solve()
{
seg.build(1, 1, n);
int l, r;
long long addVal;
while(q--)
{
cin >> l >> r >> addVal;
l++;
r++;
if(l > 1)
{
long long pre = seg.query(1, 1, n, l-1, l-1);
long long cur = seg.query(1, 1, n, l, l);
curAns -= getVal(pre, cur);
curAns += getVal(pre, cur+addVal);
}
if(r < n)
{
long long pre = seg.query(1, 1, n, r, r);
long long cur = seg.query(1, 1, n, r+1, r+1);
curAns -= getVal(pre, cur);
curAns += getVal(pre+addVal, cur);
}
seg.update(1, 1, n, l, r, addVal);
cout << curAns << '\n';
}
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
readData();
solve();
return 0;
}
