#include <bits/stdc++.h>
//#include <math.h>
using namespace std;

#define INF 1.1e9
#define LINF 1.1e18
#define FOR(i,a,b) for (int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
#define pb push_back
#define pf push_front
#define fi first
#define se second
#define BIT(x,n) bitset<n>(x)
#define PI 3.14159265358979323846

typedef long long ll;
typedef pair<int,int> P;
typedef pair<ll,P> PP;

//-----------------------------------------------------------------------------

int N,Q,S,T;
ll A[200010];
ll dif[200010];
ll now;

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	cin>>N>>Q>>S>>T;
	S=-S;
	T=-T;
	REP(i,N+1) cin>>A[i];
	REP(i,N) dif[i+1]=A[i+1]-A[i];

	REP(i,N+1) {
		now+=(dif[i]>0?S:T)*dif[i];
	}
	REP(i,Q) {
		int l,r;ll x;cin>>l>>r>>x;
		now-=(dif[l]>0?S:T)*dif[l];
		if(r<N) now-=(dif[r+1]>0?S:T)*dif[r+1];
		dif[l]+=x;
		if(r<N) dif[r+1]-=x;
		now+=(dif[l]>0?S:T)*dif[l];
		if(r<N) now+=(dif[r+1]>0?S:T)*dif[r+1];
		cout<<now<<endl;
	}
	return 0;
}

