#include<bits/stdc++.h>
typedef unsigned long long ull;
using namespace std;
const int N=2e5+10;
const ull base=1331;

ull n,q,b,k;
ull pw[N],a[N];

#define lc (p<<1)
#define rc (p<<1|1)
#define mid ((L+R)>>1)

ull dat[2][N<<2];
ull len[N<<2];

void upd(int p){
    dat[0][p]=dat[0][lc]+dat[1][rc]*len[lc];
    dat[1][p]=dat[1][lc]*len[rc]+dat[1][rc];
}

void build(int p,int L,int R){
    len[p]=R-L+1;
    if(L==R)dat[0][p]=dat[1][p]=a[L];
    else build(lc,L,mid),build(rc,mid+1,R),upd(p);
}

void change(int p,int L,int R,int x,ull w){
    if(L==R){
        dat[0][p]+=w,dat[1][p]+=w;
        return;
    }
    if(x<=mid)change(lc,L,mid,x,w);
    else change(rc,mid+1,R,x,w);
    upd(p);
}

ull ask(int op,int p,int L,int R,int l,int r){
    if(l<=L&&R<=r){
        if(op==0)return pw[L-l]*dat[op][p];
        else return pw[r-R]*dat[op][p];
    }
    if(r<=mid)return ask(op,lc,L,mid,l,r);
    else if(l>mid)return ask(op,rc,mid+1,R,l,r);
    else return ask(op,lc,L,mid,l,r)+ask(op,rc,mid+1,R,l,r);
}

#undef lc
#undef rc
#undef mid

int main(){
    ios::sync_with_stdio(0);
    cin.tie(0),cout.tie(0);
    cin>>n>>q>>k>>b;
    b*=2;
    for(int i=1;i<=n;i++){
        cin>>a[i];
        a[i]=a[i]*2-i*k;
    }
    for(int i=n;i;i--)a[i]-=a[i-1];
    pw[0]=1;
    for(int i=1;i<=n;i++)pw[i]=pw[i-1]*base;
    build(1,1,n);
    while(q--){
        ull op,l,r,w,x;
        cin>>op;
        if(op==1){
            cin>>l>>r>>w;w*=2;
            change(1,1,n,l,w);
            if(r+1<=n)change(1,1,n,r+1,-w);
        }else{
            cin>>x;
            if(x==1||x==n||ask(0,1,1,n,x,x)+ask(0,1,1,n,x+1,x+1)!=b){
                cout<<"0\n";
                continue;
            }
            int l=2,r=min(x-1,n-x);
            while(l<=r){
                int mid=(l+r)>>1;
                if(ask(0,1,1,n,x-mid+1,x-1)+ask(1,1,1,n,x+2,x+mid)!=0)r=mid-1;
                else l=mid+1;
            }
            cout<<r<<endl;
        }
    }
    return 0;
}