#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
#pragma GCC optimize("Ofast,unroll-loops,inline-functions,no-stack-protector,03")
#pragma GCC target ("sse,sse2,sse3,ssse3,sse4,popcnt,abm,avx2,mmx,fma,avx,tune=native")
#pragma clang loop vectorize(enable)
#pragma clang loop interleave(enable)
#define int long long
#define sz(x) (int)x.size()
#define F first
#define S second
#define pb push_back
#define nl '\n'
#define o_set tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update>
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
typedef pair<int, int> pii;
void file( string s = "" )
{
if( s.empty() )
return;
freopen((s + ".in").c_str(), "r", stdin);
freopen((s + ".out").c_str(), "w", stdout);
}
const int N = 2e5 + 2;
const int N1 = 1e6 + 2;
const int inf = 1e9;
const int INF = 1e18;
const int mod = 1e9 + 7;
const double eps = 1e-9;
int T = 1, n, q, x, y, a[N], cur, t[N];
void upd( int i, int add )
{
for( ; i <= n; i += i & -i )
t[i] += add;
}
int get( int i )
{
int res = 0;
for( ; i > 0; i -= i & -i )
res += t[i];
return res;
}
void solve()
{
cin >>n >>q >>x >>y;
for( int i = 0; i <= n; ++i )
{
cin >>a[i];
if( i > 0 )
cur += (a[i - 1] < a[i] ? -x : y) * abs(a[i] - a[i - 1]);
}
while( q-- )
{
int l, r, add;
cin >>l >>r >>add;
cur -= (a[l - 1] + get(l - 1) < a[l] + get(l) ? -x : y) * abs(a[l] + get(l) - a[l - 1] - get(l - 1));
if( r < n )
cur -= (a[r] + get(r) < a[r + 1] + get(r + 1) ? -x : y) * abs(a[r + 1] + get(r + 1) - a[r] - get(r));
upd(l, add);
upd(r + 1, -add);
cur += (a[l - 1] + get(l - 1) < a[l] + get(l) ? -x : y) * abs(a[l] + get(l) - a[l - 1] - get(l - 1));
if( r < n )
cur += (a[r] + get(r) < a[r + 1] + get(r + 1) ? -x : y) * abs(a[r + 1] + get(r + 1) - a[r] - get(r));
cout <<cur <<nl;
}
}
signed main()
{
file("");
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
// cin >>T;
while( T-- )
solve();
}
