#include<bits/stdc++.h>
#define inf 1e15 + 7
#define N 200005
#define ll long long
using namespace std;
ll n,q,up,down;
ll arr[N] , lazy[N<<2] , node[N<<2];
ll ans = 0;
void build_tree(ll i,ll l,ll r) {
if(l>r) return;
if(l==r) {
node[i] = arr[l];
return;
}
ll m = (l + r) / 2;
build_tree(i<<1 , l , m); m++;
build_tree(i<<1|1 , m , r);
}
void true_val(ll i,ll l,ll r) {
if(l!=r) {
node[i<<1] += lazy[i];
lazy[i<<1] += lazy[i];
node[i<<1|1] += lazy[i];
lazy[i<<1|1] += lazy[i];
lazy[i] = 0;
}
}
void update(ll i,ll l,ll r,ll a,ll b,ll val) {
if(l>r || b<l || r<a) return;
if(a<=l && r<=b) {
node[i] += val;
lazy[i] += val;
return;
}
true_val(i,l,r);
ll m = (l + r) / 2;
update(i<<1 , l , m , a , b , val); m++;
update(i<<1|1 , m , r , a , b , val);
node[i] = max(node[i<<1],node[i<<1|1]);
}
ll get_max(ll i,ll l,ll r,ll a,ll b) {
true_val(i,l,r);
if(l>r || b<l || r<a) return -inf;
if(a<=l && r<=b) return node[i];
ll m = (l + r) / 2;
return max(get_max(i<<1,l,m,a,b),get_max(i<<1|1,m+1,r,a,b));
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin>>n>>q>>down>>up;
memset(lazy,0,sizeof(lazy));
for(ll i=0;i<=n;i++) cin>>arr[i];
build_tree(1,1,n);
for(ll i=0;i<=n-1;i++) {
if(arr[i] < arr[i+1]) ans -= down * abs(arr[i] - arr[i+1]);
else ans += up * abs(arr[i] - arr[i+1]);
}
while(q--) {
ll l,r,x; cin>>l>>r>>x;
ll MAX1 = (l==1 ? 0 : get_max(1,1,n,l-1,l-1));
ll MAX2 = get_max(1,1,n,l,l);
if(MAX1 < MAX2 && MAX1 >= MAX2 + x) {
ans += down * abs(MAX1 - MAX2);
ans += up * abs(MAX1 - MAX2 - x);
}
else if(MAX1 < MAX2 && MAX1 < MAX2 + x) {
ans += down * abs(MAX1 - MAX2);
ans -= down * abs(MAX1 - MAX2 - x);
}
if(MAX1 >= MAX2 && MAX1 < MAX2 + x) {
ans -= down * abs(MAX1 - MAX2 - x);
ans -= up * abs(MAX1 - MAX2);
}
else if(MAX1 >= MAX2 && MAX1 >= MAX2 + x) {
ans -= up * abs(MAX1 - MAX2);
ans += up * abs(MAX1 - MAX2 - x);
}
if(r <= n - 1) {
ll MAX3 = get_max(1 , 1 , n , r , r);
ll MAX4 = get_max(1 , 1 , n , r + 1 , r + 1);
if(MAX3 < MAX4 && MAX3 + x >= MAX4) {
ans += down * abs(MAX3 - MAX4);
ans += up * abs(MAX3 + x - MAX4);
}
else if(MAX3 < MAX4 && MAX3 + x < MAX4) {
ans += down * abs(MAX3 - MAX4);
ans -= down * abs(MAX3 + x - MAX4);
}
if(MAX3 >= MAX4 && MAX3 + x < MAX4) {
ans -= up * abs(MAX3 - MAX4);
ans -= down * (MAX3 + x - MAX4);
}
else if(MAX3 >= MAX4 && MAX3 + x >= MAX4) {
ans -= up * abs(MAX3 - MAX4);
ans += up * abs(MAX3 + x - MAX4);
}
}
cout<<ans<<endl;
update(1,1,n,l,r,x);
}
}
