#include <bits/stdc++.h>
#define x first
#define y second
using namespace std;
using ll=long long;
using pii=pair<int,int>;
using vi=vector<int>;
using vl=vector<ll>;
#define pb push_back
#define all(a) begin(a),end(a)

const int N=200010,MOD=1e9+7,M=1<<18;
const char en='\n';
const ll LLINF=1ll<<60;
mt19937 rng(37952);
uniform_int_distribution<int> dis(4000,MOD-4000);

int n,q,k,b,a[N],p1[N];
array<int,2> seg[2][M*2+10];

array<int,2> mer1(array<int,2> a,array<int,2> b)
{
	return {(a[0]*1ll*p1[b[1]]+b[0])%MOD,a[1]+b[1]};
}

array<int,2> mer2(array<int,2> a,array<int,2> b)
{
	return {(b[0]*1ll*p1[a[1]]+a[0])%MOD,a[1]+b[1]};
}

void upd(int i,int x)
{
	i+=M;
	seg[0][i][1]=1;
	seg[1][i][1]=1;
	seg[0][i][0]=(seg[0][i][0]+x)%MOD;
	seg[1][i][0]=(seg[1][i][0]+MOD-x)%MOD;
	for (i/=2;i;i/=2) seg[0][i]=mer1(seg[0][i*2],seg[0][i*2+1]),seg[1][i]=mer2(seg[1][i*2],seg[1][i*2+1]);
}

array<int,2> ge(int j,int l,int r,int lo=0,int hi=M,int i=1)
{
	if (lo>=l && hi<=r) return seg[j][i];
	if (lo>=r || hi<=l) return {0,0};
	int mid=(lo+hi)/2;
	if (j==0) return mer1(ge(j,l,r,lo,mid,i*2),ge(j,l,r,mid,hi,i*2+1));
	else return mer2(ge(j,l,r,lo,mid,i*2),ge(j,l,r,mid,hi,i*2+1));
}

int main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int baz=dis(rng);
	p1[0]=1;
	for (int i=1;i<N;++i) p1[i]=(p1[i-1]*1ll*baz)%MOD;
	cin>>n>>q>>k>>b;
	b*=2;
	for (int i=0;i<n;++i)
	{
		cin>>a[i];
		a[i]=a[i]*2-i*k;
	}
	for (int i=1;i<n;++i)
	{
		upd(i,(a[i]-a[i-1]+MOD)%MOD);
	}
	while (q--)
	{
		int ti;
		cin>>ti;
		if (ti==1)
		{
			int l,r,x;
			cin>>l>>r>>x;
			x*=2;
			--l;
			upd(l,x);
			upd(r,-x);
		}
		else
		{
			int i;
			cin>>i;
			--i;
			if (i==0 || i==n-1)
			{
				cout<<0<<en;
				continue;
			}
			int d1=ge(0,i,i+1)[0],d2=ge(0,i+1,i+2)[0];
			if ((d1+d2)%MOD!=b)
			{
				cout<<0<<en;
				continue;
			}
			int lo=0,hi=min(i-1,n-i-2);
			int kr1=i,po2=i+2;
			while (lo<hi)
			{
				int mid=(lo+hi+1)/2;
				//cout<<mid<<' '<<i-mid<<' '<<kr1<<' '<<po2<<' '<<i+mid+2<<en;
				if (ge(0,i-mid,kr1)==ge(1,po2,i+mid+2)) lo=mid;
				else hi=mid-1;
			}
			cout<<lo+1<<en;
		}
	}
}