#include "bits/stdc++.h"
using namespace std;
#define ar array
const int N = 2e5 + 5;
struct ST{
int tree[N];
void add(int i, int v){ i++;
for(;i<N;i+=(i&-i)) tree[i] += v;
}
int get(int i){ i++;
int r=0;
for(;i>0;i-=(i&-i)) r += tree[i];
return r;
}
}tree;
signed main(){
ios::sync_with_stdio(0); cin.tie(0);
int n, q, s, t; cin>>n>>q>>s>>t;
vector<int> a(n + 1);
for(int i=0;i<=n;i++) cin>>a[i];
int res = 0;
for(int i=1;i<=n;i++){
if(a[i-1] < a[i]) res -= (a[i] - a[i-1]) * s;
else res += (a[i-1] - a[i]) * t;
tree.add(i, a[i]);
tree.add(i+1, -a[i]);
}
auto check = [&](int i, int c){
if(i <= 0 || i > n) return;
int l = tree.get(i-1), r = tree.get(i);
if(l < r) res -= (r - l) * s * c;
else res += (l - r) * t * c;
};
while(q--){
int l, r, x; cin>>l>>r>>x;
check(l, -1), check(r+1, -1);
tree.add(l, x);
tree.add(r + 1, -x);
check(l, 1), check(r+1, 1);
cout<<res<<"\n";
}
}
