#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef long long ull;
const ll N=2e5+3,H=1e9+97;
ll n,m,K,B,a[N],b[N];
ull bas=998244353,pw[N],ip[N],res[N];
ll Ksm(ll x,ll y)
{
	ll s=1;
	for(;y;y>>=1,x=x*x%H)if(y&1)s=s*x%H;
	return s;
}
struct BIT0
{
	ll tr[N];
	void Add(int x,ll y){for(;x<n;x+=x&-x)tr[x]=(tr[x]+y)%H;}
	ll Ask(int x){ll s=0;for(;x;x-=x&-x)s=(s+tr[x])%H;return s;}
	ll Ans(int l,int r){return (Ask(r)-Ask(l-1)+H)*ip[l]%H;}
}T0;
struct BIT1
{
	ll tr[N];
	void Add(int x,ll y){for(;x;x-=x&-x)tr[x]=(tr[x]+y)%H;}
	ll Ask(int x){ll s=0;for(;x<n;x+=x&-x)s=(s+tr[x])%H;return s;}
	ll Ans(int l,int r){return (Ask(l)-Ask(r+1)+H)*ip[n-r]%H;}
}T1;
int main()
{
	ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
	cin>>n>>m>>K>>B;pw[0]=res[0]=ip[0]=1;
	for(int i=1;i<N;i++)pw[i]=pw[i-1]*bas%H,res[i]=(res[i-1]+pw[i])%H,ip[i]=Ksm(pw[i],H-2);
	for(int i=1;i<=n;i++)cin>>a[i];
	for(int i=1;i<n;i++)b[i]=a[i+1]-a[i];
	for(int i=1;i<n;i++)T0.Add(i,b[i]*pw[i]%H),T1.Add(i,b[i]*pw[n-i]%H);
	while(m--)
	{
		int op;cin>>op;
		if(op==1)
		{
			int l,r,d;cin>>l>>r>>d;
			if(l>1)b[l-1]+=d,T0.Add(l-1,(H+d)*pw[l-1]%H);
			if(r<n)b[r]-=d,T1.Add(r,(H-d)*pw[n-r]%H);
		}
		else
		{
			ll x;cin>>x;
			if(x==1||b[x-1]+b[x]!=K+B){cout<<0<<"\n";continue;}
			int l=1,r=min(x-1,n-x);
			while(l<r)
			{
				int mi=(l+r)/2+1;
				ll s0=T0.Ans(x-mi,x-1),s1=T1.Ans(x,x+mi-1);
				if((s0+s1)%H==(res[mi-1]*K+pw[mi-1]*B)%H)l=mi;
				else r=mi-1;
			}
			cout<<l<<"\n";
		}
	}
}