#include<bits/stdc++.h>
using namespace std;
#define debug(x) cout << '[' << #x << " is: " << x << "] " << endl;
#define inF freopen("6in.txt" , "r" , stdin);
#define outF freopen("6.txt" , "w" , stdout);
#define imod(a , n) (a % n + n ) % n
#define sor(v) sort(v.begin() , v.end());
#define print(v) for(auto f : v ) cout << f << " " ;
#define rsor(v) sort(v.rbegin() , v.rend());
#define rev(v) reverse(v.begin() , v.end());
#define scan(v)for(auto &it : v)cin >> it ;
#define ll long long
//#define int ll
#define logar(x , y) log(x) / log(y)
#define __sum(n) n * (n + 1) / 2
#define __lcm(a , b) a / __gcd(a , b) * b
#define pii pair<int , int >
#define fastio ios_base::sync_with_stdio(false);cin.tie(0);
const int N = 1e3 + 5 , M = N * 64 , MX = 2e4 + 40;
const ll MOD = 1e9 + 7 , oo = 1e9 + 9 , OO = 1e18 , mod = MOD ;
const double pi = acos(-1) , eps = 1e-17 ;
int di[] = {1 , -1 , 0 , 0};
int dj[] = {0 , 0 , -1 , 1};
int32_t main()
{ //inF;
//inF;outF;
fastio;
int n , q , s , t ;
cin >> n>> q >> s >> t ;
long long arr[n + 1];
for(int i = 0 ; i < n + 1; i ++)cin >> arr[i];
while(q--){
int l , r , x ;
cin >> l >> r >> x ;
while(l <= r)arr[l++] += x ;
long long ans = 0 ;
for(int i = 1 ; i < n + 1 ; i ++){
//debug(arr[i])// cout << arr[i] << " ";
long long d = abs(arr[i] - arr[i - 1]);
if(arr[i - 1] < arr[i])ans -= s * d ;
else ans += t * d ;
}
cout << ans << '\n';
}
}
