#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
#pragma GCC target("sse,sse2,fma,avx,avx2")
#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;

#define int long long
#define fi first
#define se second
#define pb push_back
//#define mp make_pair

typedef pair<int, int> ii;
typedef pair<ii, int> iii;
typedef pair<ii, ii> iiii;

const int N = 3e5 + 5;

const int oo = 1e18 + 7, mod = 1e9 + 7;

mt19937 rng(1);

int n, q, s, t, a[N];

int diff[N];

int cal(int x){
    if(x > 0) return x * s;
    else return x * t;
}

void process(){
	cin >> n >> q >> s >> t;
	for(int i = 0; i <= n; i++) cin >> a[i];
	for(int i = 1; i <= n; i++) diff[i] = a[i] - a[i - 1];
	int total = 0;
	for(int i = 1; i <= n; i++){
	    total -= cal(diff[i]);
	}
	for(int i = 1; i <= q; i++){
	    int x, y, val;
	    cin >> x >> y >> val;
	    total += cal(diff[x]);
	    if((y + 1) <= n) total += cal(diff[y + 1]);
	    diff[x] += val;
	    diff[y + 1] -= val;
	    total -= cal(diff[x]);
	    if((y + 1) <= n) total -= cal(diff[y + 1]);
	    cout << total << "\n";
	}
}

signed main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	//freopen("cave.inp", "r", stdin);
	//freopen("cave.out", "w", stdout);
	process();
	//ll t;
	//cin >> t;
	//while(t--) process();
}
/*
2 3 9
1 0 0 20
1 0 2 15
1 1 1 12
2 0 0 0 2
2 0 0 1 1
1 0 1 6
1 1 1 14
2 0 0 0 2
2 0 0 1 1
*/