#include <bits/stdc++.h>
#define F first
#define S second
#define LL long long
#define rep(i, x) for(auto &i : (x))
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define left(x) ((x)<<1)
#define right(x) ((x)>>1)
#define LSOne(x) (x & -(x))
using namespace std;
using T = pair<pair<int, int>, int>;
const int SZ = 2e5 + 1;
const LL MOD = 1e9 + 7;
const LL INF = 1e18 + 1;
LL bp (LL b, LL e, LL m = MOD) {
if ( e == 0 ) return 1;
LL T = bp(b, e / 2);
T *= T; T %= m;
if ( e & 1 ) T *= b;
return T %= m;
}
LL nv_i (LL a) { return bp(a, MOD - 2); };
LL gcd (LL a, LL b) { return (b == 0 ? a : gcd(b, a % b)); }
LL lcm(LL a, LL b) { return (a * (b / gcd(a, b))); }
LL ceil (LL a, LL b) { return ((a + b - 1) / b); }
struct FTree {
int n;
vector<LL> FT;
FTree(int _n) {
n = _n;
FT.resize(n + 1);
}
void update(int pos, LL val) {
for(; pos <= n; pos += LSOne(pos)) {
FT[pos] += val;
}
}
void update(int L, int R, LL val) {
update(L, val);
update(R + 1, -val);
}
LL query(int pos) {
LL sum = 0;
for(; pos > 0; pos -= LSOne(pos)) {
sum += FT[pos];
}
return sum;
}
LL query(int L, int R) {
return query(R) - query(L - 1);
}
};
void solve() {
int n, q, s, t;
cin >> n >> q >> s >> t;
vector<LL> DIF(n + 1), V(n + 1);
vector<bool> VB(n + 1);
for(int i = 0; i <= n; i ++) cin >> V[i];
FTree FTree_0(n);
LL cnt_0 = 0, cnt_1 = 0;
for(int i = 1; i <= n; i ++) {
DIF[i] = V[i] - V[i - 1];
VB[i] = DIF[i] > 0;
if(VB[i])
cnt_1 += DIF[i];
else
cnt_0 += abs(DIF[i]);
}
for(int i = 0; i < q; i ++) {
int L, R;
LL val;
cin >> L >> R >> val;
FTree_0.update(L, R, val);
LL i_0 = V[L] + FTree_0.query(L), i_1 = V[L - 1] + FTree_0.query(L - 1);
if(VB[L])
cnt_1 -= DIF[L];
else
cnt_0 -= abs(DIF[L]);
DIF[L] = i_0 - i_1;
VB[L] = DIF[L] > 0;
if(VB[L])
cnt_1 += DIF[L];
else
cnt_0 += abs(DIF[L]);
if(R < n) {
i_0 = V[R + 1] + FTree_0.query(R + 1), i_1 = V[R] + FTree_0.query(R);
if(VB[R + 1])
cnt_1 -= DIF[R + 1];
else
cnt_0 -= abs(DIF[R + 1]);
DIF[R + 1] = i_0 - i_1;
VB[R + 1] = DIF[R + 1] > 0;
if(VB[R + 1])
cnt_1 += DIF[R + 1];
else
cnt_0 += abs(DIF[R + 1]);
}
cout << (cnt_1 * s - cnt_0 * t) * -1 << "\n";
// cout << cnt_0 * s + cnt_1 * t << "\n";
}
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0), cout.tie(0);
solve();
return 0;
}
