#include <bits/stdc++.h>
using namespace std;
#define int long long
#define N 200010
int fw[N], fw2[N];
void update(int x, int y, int v) { //inclusive
x++; y++;
for (int tx=x; tx < N; tx += tx&(-tx)) fw[tx] += v, fw2[tx] -= v*(x-1);
for (int ty=y+1; ty < N; ty += ty&(-ty)) fw[ty] -= v, fw2[ty] += v*y;
}
int sum (int x) {
x++;
int res = 0;
for (int tx=x; tx; tx -= tx&(-tx)) res += fw[tx]*x + fw2[tx];
return res;
}
inline int range_sum(int x, int y) { //inclusive
return sum(y)-sum(x-1);
}
signed main() {
int n, q, s, t;
cin >> n >> q >> s >> t;
int h[n+1];
for (int x = 0; x < n+1; x++) {cin >> h[x]; if (x != 0) update(x, x, h[x]);}
int ans = 0;
for (int x = 0; x < n; x++){
if (h[x] < h[x+1]) ans -= s * (h[x+1] - h[x]);
else ans += t * (h[x] - h[x+1]);
}
for (int x = 0; x < q; x++){
int a, b, c;
cin >> a >> b >> c; //bruh wtf need fenwick, cri
//reset to fresh
if (range_sum(a-1, a-1) < range_sum(a, a)){
ans += s * (range_sum(a, a) - range_sum(a-1, a-1));
}
else{
ans -= t * (range_sum(a-1, a-1) - range_sum(a, a));
}
if (b != n && range_sum(b, b) < range_sum(b+1, b+1)){
ans += s * (range_sum(b+1, b+1) - range_sum(b, b));
}
else if (b != n){
ans -= t * (range_sum(b, b) - range_sum(b+1, b+1));
}
update(a, b, c);
if (range_sum(a-1, a-1) < range_sum(a, a)){
ans -= s * (range_sum(a, a) - range_sum(a-1, a-1));
}
else{
ans += t * (range_sum(a-1, a-1) - range_sum(a, a));
}
if (b != n && range_sum(b, b) < range_sum(b+1, b+1)){
ans -= s * (range_sum(b+1, b+1) - range_sum(b, b));
}
else if (b != n){
ans += t * (range_sum(b, b) - range_sum(b+1, b+1));
}
cout << ans << '\n';
}
}
