/*
Author : DeMen100ns (a.k.a Vo Khac Trieu self-destruct)
School : VNU-HCM High school for the Gifted
*/
#include <bits/stdc++.h>
#define int long long
using namespace std;
template<typename T> int SIZE(T (&t)){ return t.size(); } template<typename T, size_t N> int SIZE(T (&t)[N]){ return N; } string to_string(char t){ return "'" + string({t}) + "'"; } string to_string(bool t){ return t ? "true" : "false"; } string to_string(const string &t, int x1=0, int x2=1e9){ string ret = ""; for(int i = min(x1,SIZE(t)), _i = min(x2,SIZE(t)-1); i <= _i; ++i){ ret += t[i]; } return '"' + ret + '"'; } string to_string(const char* t){ string ret(t); return to_string(ret); } template<size_t N> string to_string(const bitset<N> &t, int x1=0, int x2=1e9){ string ret = ""; for(int i = min(x1,SIZE(t)); i <= min(x2,SIZE(t)-1); ++i){ ret += t[i] + '0'; } return to_string(ret); } template<typename T, typename... Coords> string to_string(const T (&t), int x1=0, int x2=1e9, Coords... C); template<typename T, typename S> string to_string(const pair<T, S> &t){ return "(" + to_string(t.first) + ", " + to_string(t.second) + ")"; } template<typename T, typename... Coords> string to_string(const T (&t), int x1, int x2, Coords... C){ string ret = "["; x1 = min(x1, SIZE(t)); auto e = begin(t); advance(e,x1); for(int i = x1, _i = min(x2,SIZE(t)-1); i <= _i; ++i){ ret += to_string(*e, C...) + (i != _i ? ", " : ""); e = next(e); } return ret + "]"; } template<int Index, typename... Ts> struct print_tuple{ string operator() (const tuple<Ts...>& t) { string ret = print_tuple<Index - 1, Ts...>{}(t); ret += (Index ? ", " : ""); return ret + to_string(get<Index>(t)); } }; template<typename... Ts> struct print_tuple<0, Ts...> { string operator() (const tuple<Ts...>& t) { return to_string(get<0>(t)); } }; template<typename... Ts> string to_string(const tuple<Ts...>& t) { const auto Size = tuple_size<tuple<Ts...>>::value; return print_tuple<Size - 1, Ts...>{}(t); } void dbgr(){;} template<typename Heads, typename... Tails> void dbgr(Heads H, Tails... T){ cout << to_string(H) << " | "; dbgr(T...); } void dbgs(){;} template<typename Heads, typename... Tails> void dbgs(Heads H, Tails... T){ cout << H << " "; dbgs(T...); }
#define dbgv(...) cout << to_string(__VA_ARGS__) << endl;
#define dbg(...) cout << "[" << #__VA_ARGS__ << "]: "; dbgv(__VA_ARGS__);
#define dbgr(...) dbgr(__VA_ARGS__); cout << endl;
#define dbgm(...) cout << "[" << #__VA_ARGS__ << "]: "; dbgr(__VA_ARGS__);
const int N = 2e5 + 5;
const long long INF = 1e18 + 7;
const int MAXA = 1e9;
const int B = sqrt(N) + 5;
int a[N], seg[4 * N], lazy[4 * N];
int n, s, t;
void down(int id){
int t = lazy[id];
seg[id << 1] += t;
seg[id << 1 | 1] += t;
lazy[id << 1] += t;
lazy[id << 1 | 1] += t;
lazy[id] = 0;
}
void upd(int id, int l, int r, int u, int v, int val){
if (l > v || r < u) return;
if (l >= u && r <= v){
seg[id] += val;
lazy[id] += val;
return;
}
down(id);
int mid = (l + r) >> 1;
upd(id << 1, l, mid, u, v, val);
upd(id << 1 | 1, mid + 1, r, u, v, val);
}
int get(int id, int l, int r, int pos){
if (l == r) return seg[id];
down(id);
int mid = (l + r) >> 1;
if (mid >= pos) return get(id << 1, l, mid, pos);
else return get(id << 1 | 1, mid + 1, r, pos);
}
int get_ans(int p){
if (p > n) return 0;
int v2 = get(1, 1, n, p);
int v1 = 0;
if (p > 1) v1 = get(1, 1, n, p - 1);
//dbgm(v1, v2);
if (v2 > v1) return -s * (v2 - v1);
else return t * (v1 - v2);
}
void solve(){
int q, ans = 0;
cin >> n >> q >> s >> t;
for(int i = 0; i <= n; ++i) cin >> a[i];
for(int i = 1; i <= n; ++i){
if (a[i] > a[i - 1]) ans -= s * (a[i] - a[i - 1]);
else ans += t * (a[i - 1] - a[i]);
}
for(int i = 1; i <= n; ++i) upd(1, 1, n, i, i, a[i]);
while (q--){
int l, r, v;
cin >> l >> r >> v;
ans -= get_ans(l);
ans -= get_ans(r + 1);
upd(1, 1, n, l, r, v);
ans += get_ans(l);
ans += get_ans(r + 1);
cout << ans << endl;
}
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
//freopen("codeforces.inp","r",stdin);
//freopen("codeforces.out","w",stdout);
int t = 1; //cin >> t;
while(t--){
solve();
}
}
