//Sylwia Sapkowska
#include <bits/stdc++.h>
#pragma GCC optimize("O3", "unroll-loops")
using namespace std;
void __print(int x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << "'" << x << "'";}
void __print(const char *x) {cerr << '"' << x << '"';}
void __print(const string &x) {cerr << '"' << x << '"';}
void __print(bool x) {cerr << (x ? "true" : "false");}
template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ", "; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? ", " : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifdef LOCAL
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif
#define int long long
typedef pair<int, int> T;
const int oo = 1e18, oo2 = 1e9+7, K = 30;
const int mod = 998244353;
void solve(){
int n, q, s, t; cin >> n >> q >> s >> t;
vector<int>a(n+1), b(n+1);
int ans = 0;
for (int i = 0; i<=n; i++) {
cin >> a[i];
if (i) {
b[i] = a[i] - a[i-1];
if (b[i] > 0) ans -= abs(b[i])*s;
else ans += abs(b[i])*t;
}
}
debug(ans);
while (q--){
int l, r, v; cin >> l >> r >> v;
int sgn = 1;
for (auto k: {l, r+1}){
if (k > n) continue;
if (b[k] > 0) ans += abs(b[k])*s;
else ans -= abs(b[k])*t;
b[k] += sgn*v;
if (b[k] > 0) ans -= abs(b[k])*s;
else ans += abs(b[k])*t;
sgn = -sgn;
}
cout << ans << "\n";
}
}
int32_t main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t = 1;
//cin >> t;
while (t--) solve();
return 0;
}
