#ifndef LOCAL
#pragma GCC optimize("O3,unroll-loops")
#endif
#include <bits/stdc++.h>
#define fi first
#define se second
#define pn printf("\n")
#define ssize(x) int(x.size())
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define bitcount(x) __builtin_popcount(x)
#define clz(x) __builtin_clz(x)
#define ctz(x) __builtin_ctz(x)
#define mp make_pair
//~ #define r(x) resize(x)
//~ #define rf(x, c) resize(x, c)
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<int, ll> pil;
typedef pair<ll, int> pli;
typedef pair<ll, ll> pll;
typedef double db;
typedef long double ldb;
#define V vector
int inf = 2e09; ll infll = 2e18; int mod = (1<<23)*119+1;
int add(int a, int b){return a+b >= mod ? a+b - mod : a+b;}
int sub(int a, int b){return a-b < 0 ? a-b + mod : a-b;}
int mul(int a, int b){return int(a * ll(b) % mod);}
int fpow(int a, ll b){
int ret = 1;
while(b){
if(b & 1) ret = mul(ret, a);
b >>= 1, a = mul(a, a);
} return ret;
}
int inv(int a){ return fpow(a, mod-2); }
struct coeff{
V<int> fac, invfac;
coeff(int n){
fac.resize(n+1), invfac.resize(n+1);
fac[0] = 1, invfac[0] = 1;
for(int i = 1; i <= n; ++i) fac[i] = mul(fac[i-1], i);
invfac[n] = inv(fac[n]);
for(int i = n-1; i; --i) invfac[i] = mul(invfac[i+1], i+1);
}
int get(int n, int k){
if(n < k) return 0;
return mul(fac[n], mul(invfac[n-k], invfac[k]));
}
};
struct seg{
int base = 1;
V<ll> t;
seg(int n, V<int> &a){
while(base < n) base <<= 1;
t.resize(base<<1, 0);
for(int i = 1; i <= n; ++i) t[i+base-1] = a[i];
}
void update(int l, int r, ll val){
for(l += base-1, r += base; l < r; l >>= 1, r >>= 1){
if(l&1) t[l++] += val;
if(r&1) t[--r] += val;
}
}
ll query(int i){
ll ret = 0;
for(i += base-1; i; i >>= 1) ret += t[i];
return ret;
}
};
void answer(){
int n, q, S, T; scanf("%d%d%d%d", &n, &q, &S, &T);
V<int> t(n+1, 0);
for(int i = 0; i <= n; ++i) scanf("%d", &t[i]);
seg seg(n, t);
ll result = 0;
auto move = [&] (int i){
if(!i){
ll b = seg.query(1);
return 0 < b ? b*(-S) : b*T;
}
if(i == n) return 0ll;
ll a = seg.query(i), b = seg.query(i+1);
return a < b ? -S*(b-a) : T*(a-b);
};
for(int i = 0; i <= n; ++i) result += move(i);
// printf("%lld\n", result);
for(++q; --q; ){
int l, r, val; scanf("%d%d%d", &l, &r, &val);
result -= move(l-1), result -= move(r);
seg.update(l, r, val);
result += move(l-1), result += move(r);
printf("%lld\n", result);
}
}
int main(){
int T = 1;
// scanf("%d", &T);
//~ ios_base::sync_with_stdio(0); cin.tie(0); cin >> T;
for(++T; --T; ) answer();
return 0;
}
