#pragma GCC optimize(2)
#pragma G++ optimize(2)
#include<bits/stdc++.h>
using namespace std;
const int MAXN=4e5+5;
const int MAXK=4e3+5;
const int seed=2333;
unsigned int n,q,k,b;
unsigned long long a[MAXN],c[MAXN],tr1[MAXN*4],tr2[MAXN*4],tag1[MAXN*4],tag2[MAXN*4],pre[MAXN],qp[MAXN];
void prep(){
    qp[0]=1;
    for(int i=1;i<=n;i++){
        qp[i]=qp[i-1]*seed;
        pre[i]=(pre[i-1]+qp[i-1]);
    }
}
void pushup(int rt,int l,int r){
    int mid=l+r>>1;
    tr1[rt]=(tr1[rt<<1]*qp[r-mid]+tr1[rt<<1|1]);
    tr2[rt]=(tr2[rt<<1]*qp[r-mid]+tr2[rt<<1|1]);
}
void build(int rt,int l,int r,int opt){
    if(l==r){
        if(!opt) tr1[rt]=c[l];
        else tr2[rt]=c[n-l+1]-(long long)2*b;
        return ;
    }
    int mid=l+r>>1;
    build(rt<<1,l,mid,opt);
    build(rt<<1|1,mid+1,r,opt);
    pushup(rt,l,r);
}
void pushdown(int rt,int l,int r){
    int mid=l+r>>1;
    tag1[rt<<1]=(tag1[rt<<1]+tag1[rt]),tag1[rt<<1|1]=(tag1[rt<<1|1]+tag1[rt]);
    tag2[rt<<1]=(tag2[rt<<1]+tag2[rt]),tag2[rt<<1|1]=(tag2[rt<<1|1]+tag2[rt]);   
    tr1[rt<<1]=(tr1[rt<<1]+tag1[rt]*pre[mid-l+1]),tr1[rt<<1|1]=(tr1[rt<<1|1]+tag1[rt]*pre[r-mid]);
    tr2[rt<<1]=(tr2[rt<<1]+tag2[rt]*pre[mid-l+1]),tr2[rt<<1|1]=(tr2[rt<<1|1]+tag2[rt]*pre[r-mid]);
    tag1[rt]=tag2[rt]=0;
}
void update(int rt,int l,int r,int L,int R,long long p,int opt){
    if(L<=l && R>=r){
        if(!opt) tag1[rt]=(tag1[rt]+p),tr1[rt]=(tr1[rt]+pre[r-l+1]*(long long)p);
        else tag2[rt]=(tag2[rt]+p),tr2[rt]=(tr2[rt]+pre[r-l+1]*(long long)p);
        return ;
    }
    pushdown(rt,l,r);
    int mid=l+r>>1;
    if(L<=mid){
        update(rt<<1,l,mid,L,R,p,opt);
    }
    if(R>mid){
        update(rt<<1|1,mid+1,r,L,R,p,opt);
    }
    pushup(rt,l,r);
    return ;
}
long long query(int rt,int l,int r,int L,int R,int opt){
    if(L<=l && R>=r){
        if(!opt){
            return tr1[rt];
        }
        else{
            return tr2[rt];
        }
    }
    pushdown(rt,l,r);
    int mid=l+r>>1;
    long long ret=0;
    if(L<=mid){
        ret=query(rt<<1,l,mid,L,R,opt);
    }
    if(R>mid){
        ret=(ret*qp[max(0,min(r,R)-mid)]+query(rt<<1|1,mid+1,r,L,R,opt));
    }
    pushup(rt,l,r);
    return ret;
}
int check(int x,int mid){
    // cout<<query(1,1,n,x-mid,x-1,0)<<" "<<query(1,1,n,n-x-mid+1,n-x,1)<<endl;
    if(query(1,1,n,x-mid,x-1,0)==query(1,1,n,n-x-mid+1,n-x,1)){
        return 1;
    }
    return 0;
}
int main(){
	ios::sync_with_stdio(false);
	cin.tie(NULL); cout.tie(NULL);
    cin>>n>>q>>k>>b;
    prep();
    for(int i=1;i<=n;i++){
        cin>>a[i];
        c[i]=(2*a[i]-(long long)i*k);
    }
    build(1,1,n,0);
    build(1,1,n,1);
    while(q--){
        int opt;
        cin>>opt;
        if(opt==1){
            unsigned long long l,r,v;
            cin>>l>>r>>v;
            update(1,1,n,l,r,(long long)2*v,0);
            update(1,1,n,n-r+1,n-l+1,(long long)2*v,1);
        }
        else{
            int x;
            cin>>x;
            int l=1,r=min((unsigned int)x-1,n-x);
            while(l<=r){
                int mid=l+r>>1;
                if(check(x,mid)){
                    l=mid+1;
                }
                else{
                    r=mid-1;
                }
            }
            cout<<r<<'\n';
        }
    }
}