#include <bits/stdc++.h>
#define loop(i,a,b) for(int i = (a); i < (b); i ++)
using namespace std;
typedef long long ll;
const int mxn = 200005;
ll S, T;
ll a[mxn], b[mxn];
ll cal(ll pre, ll nxt){
if(nxt > pre) return (-S) * abs(nxt - pre);
else return T * abs(pre - nxt);
}
ll cal(ll det){
if(det > 0) return (-S) * abs(det);
else return T * abs(det);
}
int main(){
ios::sync_with_stdio(false); cin.tie(0);
// freopen("in.txt", "r", stdin);
int n, q; cin >> n >> q;
cin >> S >> T;
// S: decrease (go up), T: increase (go down)
loop(i,0,n+1) cin >> a[i];
ll now = 0;
loop(i,1,n+1){
b[i] = cal(a[i-1], a[i]);
now += b[i];
// cout << now << '\n';
}
for(int i = n; i >= 1; i--){
a[i] = a[i] - a[i-1];
}
// loop(i,0,n+1){
// cout << a[i] << ' ';
// } cout << '\n';
loop(queries,0,q){
int l, r; ll val;
cin >> l >> r >> val;
ll nxt_a = a[l] + val;
ll nxt_b = cal(nxt_a);
now -= b[l];
b[l] = nxt_b;
now += b[l];
a[l] = nxt_a;
if(r == n){
cout << now << '\n';
continue;
}
nxt_a = a[r+1] - val;
nxt_b = cal(nxt_a);
now -= b[r+1];
b[r+1] = nxt_b;
now += b[r+1];
a[r+1] = nxt_a;
cout << now << '\n';
}
}
