//#define NDEBUG
#include <bits/stdc++.h>
#include <bits/extc++.h>
#define StarBurstStream ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define iter(a) a.begin(), a.end()
#define riter(a) a.rbegin(), a.rend()
#define lsort(a) sort(iter(a))
#define gsort(a) sort(riter(a))
#define pb(a) push_back(a)
#define eb(a) emplace_back(a)
#define pf(a) push_front(a)
#define pob pop_back()
#define pof pop_front()
#define mp(a, b) make_pair(a, b)
#define F first
#define S second
#define mt make_tuple
#define gt(t, i) get<i>(t)
#define iceil(a, b) ((a + b - 1) / b)
#define tomax(a, b) (a = max(a, b))
#define printv(a, b) {bool pvaspace=false; \
for(auto pva : a){ \
if(pvaspace) b << " "; pvaspace=true;\
b << pva;\
}\
b << "\n";}
//#define TEST
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pdd = pair<ld, ld>;
using tiii = tuple<int, int, int>;
const ll MOD = 1000000007;
const ll MAX = 2147483647;
template<typename A, typename B>
ostream& operator<<(ostream& o, pair<A, B> p){
return o << '(' << p.F << ',' << p.S << ')';
}
int lowbit(int x){
return x & -x;
}
struct BIT{
vector<ll> bit;
explicit BIT(int sz = 0){
bit.resize(sz + 2);
}
void modify(int x, ll v){
for(; x < bit.size(); x += lowbit(x)){
bit[x] += v;
}
}
ll query(int x){
ll ans = 0;
for(; x > 0; x -= lowbit(x)){
ans += bit[x];
}
return ans;
}
ll query(int l, int r){
return query(r) - query(l - 1);
}
};
struct RUBIT{
BIT bit1;
BIT bit2;
explicit RUBIT(int sz){
bit1 = BIT(sz + 1);
bit2 = BIT(sz + 1);
}
void modify(int l, int r, ll v){
bit1.modify(l, v);
bit1.modify(r + 1, -v);
bit2.modify(l, l * v);
bit2.modify(r + 1, -(r + 1) * v);
}
ll query(int x){
return (x + 1) * bit1.query(x) - bit2.query(x);
}
ll query(int l, int r){
return query(r) - query(l - 1);
}
};
int main(){
StarBurstStream
int n, q, s, t;
cin >> n >> q >> s >> t;
RUBIT alt(n);
BIT dec(n), inc(n);
for(int i = 0; i <= n; i++){
int a;
cin >> a;
if(i != 0) alt.modify(i, i, a);
}
for(int i = 1; i <= n; i++){
if(alt.query(i - 1, i - 1) < alt.query(i, i)){
dec.modify(i, alt.query(i, i) - alt.query(i - 1, i - 1));
}
else{
inc.modify(i, alt.query(i, i) - alt.query(i - 1, i - 1));
}
}
while(q--){
int l, r, x;
cin >> l >> r >> x;
if(alt.query(l - 1, l - 1) < alt.query(l, l)) dec.modify(l, -(alt.query(l, l) - alt.query(l - 1, l - 1)));
else inc.modify(l, -(alt.query(l, l) - alt.query(l - 1, l - 1)));
if(alt.query(r, r) < alt.query(r + 1, r + 1)) dec.modify(r + 1, -(alt.query(r + 1, r + 1) - alt.query(r, r)));
else inc.modify(r + 1, -(alt.query(r + 1, r + 1) - alt.query(r, r)));
alt.modify(l, r, x);
if(alt.query(l - 1, l - 1) < alt.query(l, l)) dec.modify(l, (alt.query(l, l) - alt.query(l - 1, l - 1)));
else inc.modify(l, (alt.query(l, l) - alt.query(l - 1, l - 1)));
if(alt.query(r, r) < alt.query(r + 1, r + 1)) dec.modify(r + 1, (alt.query(r + 1, r + 1) - alt.query(r, r)));
else inc.modify(r + 1, (alt.query(r + 1, r + 1) - alt.query(r, r)));
// for(int i = 0; i <= n; i++) cerr << alt.query(i, i) << " ";
// cerr << "\n";
// for(int i = 0; i <= n; i++) cerr << dec.query(i, i) << " ";
// cerr << "\n";
// for(int i = 0; i <= n; i++) cerr << inc.query(i, i) << " ";
// cerr << "\n";
cout << -dec.query(n) * s - inc.query(n) * t << "\n";
}
return 0;
}
