#include <bits/stdc++.h>
using namespace std;
#define all(x) x.begin(), x.end()
#define srtl(x)sort(all(x))
#define srtg(x)sort((x).begin(),(x).end(),greater<>())
#define rev(x) reverse(all(x))
#define lb(x,y) lower_bound(x.begin(),x.end(),y)-x.begin()
#define ub(x,y) upper_bound(x.begin(),x.end(),y)-x.begin()
#define ios ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define f first
#define s second
#define pb push_back
#define ins insert
#define next next_permutation
#define _b __builtin_popcount
#define ve vector
#define pii pair<int,int>
#define piii pair<int,pii>
#define vi vector<int>
#define vii vector<pii>
#define viii vector<piii>
#define vvi vector<vi>
#define vs vector<string>
#define vb vector<bool>
#define pV(x)for(auto i:x)cout<<i<<" ";
#define geta(a){for(auto &i:a)cin>>i;}
#define fr(n)for(int i=0;i<n;i++)
#define Fr(n)for(int i=n-1;i>=0;i--)
#define suma(a)accumulate(a.begin(),a.end(),0LL)
#define br(x){cout<<x<<"\n";return;}
#define yesn cout<<"YES\n";
#define yes()br("YES");
#define no(){br("NO")}
#define alice() br("Alice");
#define bob() br("Bob");
#define cn continue;
#define cint const int
#define int long long
int mod=1000000007;
cint mod1=100000007;
cint mod2=998244353;
int ax[8]={0,1,0,-1,-1,1,1,-1};
int ay[8]={1,0,-1,0,1,-1,1,-1};
//bool on(int x,int y){return (x>=0&&x<n&&y>=0&&y<m);}
//int euc(int a,int b,int c,int d){return abs(a-c)+abs(b-d);}
int bp(int x,int y){
if(y==0)return 1;
int r=bp(x,y/2);
return (y&1)?r*r%mod*x%mod:r*r%mod;
}
int bpm(int x,int y){
if(y==0)return 1;
int r=bp(x,y/2);
return (y&1)?r*r*x:r*r;
}
cint N=200006;
int F[N+1],I[N+1];
int cmb(int n,int k){
return (((F[n]*I[k])%mod)*I[n-k])%mod;
}
int n,q,x,y;
int to(int num){
if(num<0)return num*x;
return num*y;
}
void solve(){
cin>>n>>q>>x>>y;n++;
vi a(n);
geta(a);
int res=0;
vi d(n+1,0);
for(int i=0;i+1<n;i++){
int num=a[i]-a[i+1];
res+=to(num);
d[i]=num;
}
while(q--){
int l,r,k;
cin>>l>>r>>k;
res-=to(d[l-1]);
d[l-1]-=k;
res+=to(d[l-1]);
if(r<n-1){
res-=to(d[r]);
d[r]+=k;
res+=to(d[r]);
}
cout<<res<<"\n";
}
//if(){yes();}
//else{no();}
cout<<"\n";
}
int32_t main(){
ios;
solve();
return 0;
}
