#include<bits/stdc++.h>
#define ll long long
#define sz(x) (signed)x.size()
#define pb push_back
#define ff first
#define ss second
#define endl '\n'
#define For(i,l,r) for(int i=l;i<=r;i++)
#define ForD(i,l,r) for(int i=r;i>=l;i--)
#define F "C"
#define fio freopen(F".inp","r",stdin);freopen(F".out","w",stdout);

using namespace std;

#ifdef NCGM
#include<C:/NCGM/headers/debug.h>
#else
#define debug(...) "mmb"
#endif

const int N=2e5+3,MOD=1e9+7,BASE=10007;

int n,q,k,b,a[N],b1[N];
ll POW[N];

struct BIT {
    ll pf[N];
    void upd(int idx,int val) {
        if (idx<=0) return;
        while(idx<=n) {
            pf[idx]+=val;
            idx+=idx&(-idx);
        }
    }
    ll query(int idx) {
        ll ans=0;
        while(idx>0) {
            ans+=pf[idx];
            idx-=idx&(-idx);
        }
        return ans;
    }
    void update(int l,int r,int val) {
        upd(l,val);
        upd(r+1,-val);
    }
} bit;

struct Node {
    ll hsh;
    int l,r;
    Node(ll hsh=0,int l=0,int r=0): hsh(hsh),l(l),r(r) {};
} st[4*N],st1[4*N];
Node mrg(const Node &A,const Node &B) {
    if (A.l<0) return B;
    if (B.l<0) return A;
    Node ans(B.hsh,A.l,B.r);
    ans.hsh=(B.hsh+A.hsh*POW[B.r-B.l+1]);
    return ans;
}
void build(int id,int l,int r,int *src,Node *out) {
    if (l==r) {
        out[id]=Node(src[l],l,l);
        return;
    }
    int mid=l+r>>1;
    build(id*2,l,mid,src,out);
    build(id*2+1,mid+1,r,src,out);
    out[id]=mrg(out[id*2],out[id*2+1]);
}
void update(int id,int l,int r,int u,int val,Node *out) {
    if (l>u || r<u) return;
    if (l==r)return void(out[id]=Node(out[id].hsh+val,l,l));

    int mid=l+r>>1;
    update(id*2,l,mid,u,val,out);
    update(id*2+1,mid+1,r,u,val,out);
    out[id]=mrg(out[id*2],out[id*2+1]);
}
Node query(int id,int l,int r,int u,int v,Node *in) {
    if (l>v || r<u) return Node(0,-1,-1);
    if (l>=u && r<=v) return in[id];
    int mid=l+r>>1;
    return mrg(query(id*2,l,mid,u,v,in),query(id*2+1,mid+1,r,u,v,in));
}
bool check(int l,int r) {
    if (l<=0 || r>n) return 0;
    if ((r-l)%2) return 0;
    return (bit.query(r)-bit.query(l)==k*((r-l)/2)+b);
}
void refine(int x) {
    if (x<=0 || x>n-2) return;
    int nw=bit.query(x)-2*bit.query(x+1)+bit.query(x+2);
    int old=query(1,1,n-2,x,x,st).hsh;
    update(1,1,n-2,x,nw-old,st);
    update(1,1,n-2,n-x-1,nw-old,st1);
}
int main() {
    //fio
    cin.tie(0)->sync_with_stdio(0);
    cin >> n >> q >> k >> b;
    POW[0]=1;
    For(i,1,n) POW[i]=POW[i-1]*BASE;
    For(i,1,n) cin >> a[i];
    For(i,1,n-2) b1[i]=a[i+2]-2*a[i+1]+a[i];
    //For(i,1,n-2) cout << b1[i] << " ";
    //cout << endl;
    build(1,1,n-2,b1,st);
    reverse(b1+1,b1+n-1);
    build(1,1,n-2,b1,st1);
    For(i,1,n) bit.update(i,i,a[i]);
    /*For(i,1,n-2) cout << query(1,1,n-2,i,i,st).hsh << " ";
    cout << endl;
    For(i,1,n-2) cout << query(1,1,n-2,i,i,st1).hsh << " ";
    cout << endl;*/
    while(q--) {
        int t;
        cin >> t;
        if (t==1) {
            int l,r,val;
            cin >> l >> r >> val;
            bit.update(l,r,val);
            refine(r-1);
            refine(r);
            refine(l-1);
            refine(l-2);
            /*For(i,1,n-2) cout << query(1,1,n-2,i,i,st).hsh << " ";
            cout << endl;
            For(i,1,n-2) cout << query(1,1,n-2,i,i,st1).hsh << " ";
            cout << endl;&*/
        } else {
            int i;
            cin >> i;
            if (!check(i-3,i+3) && check(i-2,i+2) && check(i-1,i+1)) {
                cout << 2 << endl;
                continue;
            }
            if (!check(i-2,i+2) && check(i-1,i+1)) {
                cout << 1 << endl;
                continue;
            }
            if (!check(i-1,i+1)) {
                cout << 0 << endl;
                continue;
            }
            int l=1,r=min(i-3,n-i-2);
            while(l<r) {
                int mid=l+(r-l+1)/2;
                if (query(1,1,n-2,i-mid-2,i-3,st).hsh==query(1,1,n-2,n-i-mid-1,n-i-2,st1).hsh) l=mid;
                else r=mid-1;
            }
            int tmp=l;
            l=3,r=tmp+2;
            while(l<r) {
                int mid=l+(r-l+1)/2;
                if (check(i-mid,i+mid) && check(i-mid+1,i+mid-1)) l=mid;
                else r=mid-1;
            }
            cout << l << endl;
        }
    }
    return 0;
}