#include <iostream>
#include <unordered_map>
using namespace std;
long long N;
long long* A;
unordered_map<long long, long long> M;
long long g(long long p1, long long p2)
{
return (N+1)*p1 + p2;
}
void build(long long p1, long long p2)
{
if(p1 == p2) M[g(p1, p2)] = A[p1];
else
{
build(p1, (p1+p2)/2);
build((p1+p2)/2 + 1, p2);
M[g(p1, p2)] = 0;
}
}
long long E(long long p1, long long p2, long long p)
{
if(p1 == p2) return M[g(p1, p2)];
if(p <= (p1+p2)/2) return M[g(p1, p2)] + E(p1, (p1+p2)/2, p);
else return M[g(p1, p2)] + E((p1+p2)/2 + 1, p2, p);
}
long long F(long long p)
{
if(p == 0) return 0;
return E(1, N, p);
}
void update(long long p1, long long p2, long long a1, long long a2, long long u) //map range, update range, update value
{
if(a2 < p1 || p2 < a1) return;
if(a1 <= p1 && p2 <= a2)
{
M[g(p1, p2)] += u;
return;
}
if(a1 <= (p1+p2)/2) update(p1, (p1+p2)/2, a1, a2, u);
if(a2 > (p1+p2)/2) update((p1+p2)/2 + 1, p2, a1, a2, u);
}
int main()
{
long long Q, S, T;
cin >> N >> Q >> S >> T;
A = new long long[N+1];
for(long long i = 0; i <= N; i++) cin >> A[i];
build(1, N);
long long w = 0;
for(long long i = 1; i <= N; i++) w += (A[i-1]-A[i]) * ((A[i]>A[i-1])?S:T);
long long l, r, u;
long long L1, L2, R1, R2;
for(long long i = 1; i <= Q; i++)
{
cin >> l >> r >> u;
L1 = F(l-1);
L2 = F(l);
if(r != N)
{
R1 = F(r);
R2 = F(r+1);
}
w -= (L1-L2) * ((L2>L1)?S:T);
if(r != N) w -= (R1-R2) * ((R2>R1)?S:T);
update(1, N, l, r, u);
L1 = F(l-1);
L2 = F(l);
if(r != N)
{
R1 = F(r);
R2 = F(r+1);
}
w += (L1-L2) * ((L2>L1)?S:T);
if(r != N) w += (R1-R2) * ((R2>R1)?S:T);
cout << w << '\n';
}
return 0;
}
