#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

int const N=200100;
int n,q,s,t;
ll tem[N],c[N];

int lowbit(int x){
    return x&-x;
}

void add(int l,int r,ll x){
    if (!l && !r){
        c[0]+=x;
        return;
    }
    while (l<=n){
        c[l]+=x;
        l+=lowbit(l);
    }
    r++;
    while (r<=n){
        c[r]-=x;
        r+=lowbit(r);
    }
    return;
}

ll query(int x){
    if (x<0) return 0;
    ll cnt=0;
    while (x){
        cnt+=c[x];
        x-=lowbit(x);
    }
    return cnt;
}

int main(){
    freopen("foehn.in","r",stdin);
    freopen("foehn.out","w",stdout);
    
    int a,b=0;
    ll w;
    scanf("%d %d %d %d",&n,&q,&s,&t);
    for (int i=0;i<=n;i++){
        scanf("%d",&a);
        add(i,i,a);
        //c[i]=a;
        if (!i) continue;
        if (a==b) tem[a]=tem[b];
        else if (a>b) tem[i]=tem[i-1]-s*(a-b);
        else tem[i]=tem[i-1]+t*(b-a);
        b=a;
    }
    for (int x=1;x<=q;x++){
        scanf("%d %d %lld",&a,&b,&w);
        ll frt,bck;
        ll c1=query(a-1),c2=query(a),c3=query(b),c4=query(b+1);
        if (c1<c2) frt=-w*s;
        else if (c1>c2 && c1>c2+w) frt=-w*t;
        else frt=-(c1-c2)*t-(w-c1+c2)*s;
        if (b==n) bck=0;
        else if (c3>c4) bck=w*t;
        else if (c3<c4 && c3+w<c4) bck=w*s;
        else bck=(c4-c3)*s+(w-c4+c3)*t;
        tem[n]+=frt+bck;
        add(a,b,w);
        printf("%lld\n",tem[n]);
    }
    
    return 0;
}