由于区间更改不会影响区间内点的相对大小,只要维护x和y+1两个点即可,注意y==n时不用修改
#include <bits/stdc++.h>
using namespace std;
int a[200005];
long long f[2000005];
int read(){
int x = 0,dign = 1;
char c = getchar();
while(c<'0'||c>'9'){
if(c=='-')dign=-1;
c = getchar();
}
while(c>='0'&&c<='9'){
x = 10*x+c-'0';
c = getchar();
}
return x*dign;
}
int main()
{
int n,s,t,q; long long b =0;
n = read(); q = read(); s = read(); t = read();
for(int i=0;i<=n;i++){
scanf("%d",&a[i]);
if(i>=1)f[i] = a[i] - a[i-1];
b+= f[i]*(f[i] > 0 ? -s : -t);
}
int x,y,z;
while(q--){
x = read(); y = read(); z = read();
b-= f[x]*(f[x] > 0 ? -s : -t);
b+= (f[x]+z)*( f[x]+z > 0 ? -s : -t );
f[x]+=z;
if(y!=n){
b-= f[y+1]*(f[y+1] > 0 ? -s : -t);
b+= (f[y+1]-z)*( f[y+1]-z > 0 ? -s : -t );
f[y+1]-=z;
}
printf("%lld\n",b);
}
return 0;
}