#include <cassert>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <functional>
#include <iostream>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;

using Int = long long;

template <class T1, class T2> ostream &operator<<(ostream &os, const pair<T1, T2> &a) { return os << "(" << a.first << ", " << a.second << ")"; };
template <class T> ostream &operator<<(ostream &os, const vector<T> &as) { const int sz = as.size(); os << "["; for (int i = 0; i < sz; ++i) { if (i >= 256) { os << ", ..."; break; } if (i > 0) { os << ", "; } os << as[i]; } return os << "]"; }
template <class T> void pv(T a, T b) { for (T i = a; i != b; ++i) cerr << *i << " "; cerr << endl; }
template <class T> bool chmin(T &t, const T &f) { if (t > f) { t = f; return true; } return false; }
template <class T> bool chmax(T &t, const T &f) { if (t < f) { t = f; return true; } return false; }
#define COLOR(s) ("\x1b[" s "m")

////////////////////////////////////////////////////////////////////////////////
// 2^61 - 1 = 2'305'843'009'213'693'951
struct ModLong61 {
  static constexpr unsigned long long M = (1ULL << 61) - 1;
  unsigned long long x;
  constexpr ModLong61() : x(0ULL) {}
  constexpr ModLong61(unsigned x_) : x(x_) {}
  constexpr ModLong61(unsigned long long x_) : x(x_ % M) {}
  constexpr ModLong61(int x_) : x((x_ < 0) ? (x_ + static_cast<long long>(M)) : x_) {}
  constexpr ModLong61(long long x_) : x(((x_ %= static_cast<long long>(M)) < 0) ? (x_ + static_cast<long long>(M)) : x_) {}
  ModLong61 &operator+=(const ModLong61 &a) { x = ((x += a.x) >= M) ? (x - M) : x; return *this; }
  ModLong61 &operator-=(const ModLong61 &a) { x = ((x -= a.x) >= M) ? (x + M) : x; return *this; }
  ModLong61 &operator*=(const ModLong61 &a) {
    const unsigned __int128 y = static_cast<unsigned __int128>(x) * a.x;
    x = (y >> 61) + (y & M);
    x = (x >= M) ? (x - M) : x;
    return *this;
  }
  ModLong61 &operator/=(const ModLong61 &a) { return (*this *= a.inv()); }
  ModLong61 pow(long long e) const {
    if (e < 0) return inv().pow(-e);
    ModLong61 a = *this, b = 1ULL; for (; e; e >>= 1) { if (e & 1) b *= a; a *= a; } return b;
  }
  ModLong61 inv() const {
    unsigned long long a = M, b = x; long long y = 0, z = 1;
    for (; b; ) { const unsigned long long q = a / b; const unsigned long long c = a - q * b; a = b; b = c; const long long w = y - static_cast<long long>(q) * z; y = z; z = w; }
    assert(a == 1ULL); return ModLong61(y);
  }
  ModLong61 operator+() const { return *this; }
  ModLong61 operator-() const { ModLong61 a; a.x = x ? (M - x) : 0ULL; return a; }
  ModLong61 operator+(const ModLong61 &a) const { return (ModLong61(*this) += a); }
  ModLong61 operator-(const ModLong61 &a) const { return (ModLong61(*this) -= a); }
  ModLong61 operator*(const ModLong61 &a) const { return (ModLong61(*this) *= a); }
  ModLong61 operator/(const ModLong61 &a) const { return (ModLong61(*this) /= a); }
  template <class T> friend ModLong61 operator+(T a, const ModLong61 &b) { return (ModLong61(a) += b); }
  template <class T> friend ModLong61 operator-(T a, const ModLong61 &b) { return (ModLong61(a) -= b); }
  template <class T> friend ModLong61 operator*(T a, const ModLong61 &b) { return (ModLong61(a) *= b); }
  template <class T> friend ModLong61 operator/(T a, const ModLong61 &b) { return (ModLong61(a) /= b); }
  explicit operator bool() const { return x; }
  bool operator==(const ModLong61 &a) const { return (x == a.x); }
  bool operator!=(const ModLong61 &a) const { return (x != a.x); }
  friend std::ostream &operator<<(std::ostream &os, const ModLong61 &a) { return os << a.x; }
};
////////////////////////////////////////////////////////////////////////////////

#include <chrono>
#ifdef LOCAL
mt19937_64 rng(58);
#else
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
#endif

const ModLong61 BASE = static_cast<unsigned long long>(rng());

////////////////////////////////////////////////////////////////////////////////


// T: monoid representing information of an interval.
//   T()  should return the identity.
//   T(S s)  should represent a single element of the array.
//   T::push(T &l, T &r)  should push the lazy update.
//   T::pull(const T &l, const T &r)  should pull two intervals.
template <class T> struct SegmentTreeRange {
  int logN, n;
  vector<T> ts;
  SegmentTreeRange() : logN(0), n(0) {}
  explicit SegmentTreeRange(int n_) {
    for (logN = 0, n = 1; n < n_; ++logN, n <<= 1) {}
    ts.resize(n << 1);
  }
  template <class S> explicit SegmentTreeRange(const vector<S> &ss) {
    const int n_ = ss.size();
    for (logN = 0, n = 1; n < n_; ++logN, n <<= 1) {}
    ts.resize(n << 1);
    for (int i = 0; i < n_; ++i) at(i) = T(ss[i]);
    build();
  }
  T &at(int i) {
    return ts[n + i];
  }
  void build() {
    for (int u = n; --u; ) pull(u);
  }

  inline void push(int u) {
    ts[u].push(ts[u << 1], ts[u << 1 | 1]);
  }
  inline void pull(int u) {
    ts[u].pull(ts[u << 1], ts[u << 1 | 1]);
  }

  // Applies T::f(args...) to [a, b).
  template <class F, class... Args>
  void ch(int a, int b, F f, Args &&... args) {
    assert(0 <= a); assert(a <= b); assert(b <= n);
    if (a == b) return;
    a += n; b += n;
    for (int h = logN; h; --h) {
      const int aa = a >> h, bb = b >> h;
      if (aa == bb) {
        if ((aa << h) != a || (bb << h) != b) push(aa);
      } else {
        if ((aa << h) != a) push(aa);
        if ((bb << h) != b) push(bb);
      }
    }
    for (int aa = a, bb = b; aa < bb; aa >>= 1, bb >>= 1) {
      if (aa & 1) (ts[aa++].*f)(args...);
      if (bb & 1) (ts[--bb].*f)(args...);
    }
    for (int h = 1; h <= logN; ++h) {
      const int aa = a >> h, bb = b >> h;
      if (aa == bb) {
        if ((aa << h) != a || (bb << h) != b) pull(aa);
      } else {
        if ((aa << h) != a) pull(aa);
        if ((bb << h) != b) pull(bb);
      }
    }
  }

  // Calculates the product for [a, b).
  T get(int a, int b) {
    assert(0 <= a); assert(a <= b); assert(b <= n);
    if (a == b) return T();
    a += n; b += n;
    for (int h = logN; h; --h) {
      const int aa = a >> h, bb = b >> h;
      if (aa == bb) {
        if ((aa << h) != a || (bb << h) != b) push(aa);
      } else {
        if ((aa << h) != a) push(aa);
        if ((bb << h) != b) push(bb);
      }
    }
    T prodL, prodR, t;
    for (int aa = a, bb = b; aa < bb; aa >>= 1, bb >>= 1) {
      if (aa & 1) { t.pull(prodL, ts[aa++]); prodL = t; }
      if (bb & 1) { t.pull(ts[--bb], prodR); prodR = t; }
    }
    t.pull(prodL, prodR);
    return t;
  }

  // Calculates T::f(args...) of a monoid type for [a, b).
  //   op(-, -)  should calculate the product.
  //   e()  should return the identity.
  template <class Op, class E, class F, class... Args>
#if __cplusplus >= 201402L
  auto
#else
  decltype((std::declval<T>().*F())())
#endif
  get(int a, int b, Op op, E e, F f, Args &&... args) {
    assert(0 <= a); assert(a <= b); assert(b <= n);
    if (a == b) return e();
    a += n; b += n;
    for (int h = logN; h; --h) {
      const int aa = a >> h, bb = b >> h;
      if (aa == bb) {
        if ((aa << h) != a || (bb << h) != b) push(aa);
      } else {
        if ((aa << h) != a) push(aa);
        if ((bb << h) != b) push(bb);
      }
    }
    auto prodL = e(), prodR = e();
    for (int aa = a, bb = b; aa < bb; aa >>= 1, bb >>= 1) {
      if (aa & 1) prodL = op(prodL, (ts[aa++].*f)(args...));
      if (bb & 1) prodR = op((ts[--bb].*f)(args...), prodR);
    }
    return op(prodL, prodR);
  }

  // Find min b s.t. T::f(args...) returns true,
  // when called for the partition of [a, b) from left to right.
  //   Returns n + 1 if there is no such b.
  template <class F, class... Args>
  int findRight(int a, F f, Args &&... args) {
    assert(0 <= a); assert(a <= n);
    if ((T().*f)(args...)) return a;
    if (a == n) return n + 1;
    a += n;
    for (int h = logN; h; --h) push(a >> h);
    for (; ; a >>= 1) if (a & 1) {
      if ((ts[a].*f)(args...)) {
        for (; a < n; ) {
          push(a);
          if (!(ts[a <<= 1].*f)(args...)) ++a;
        }
        return a - n + 1;
      }
      ++a;
      if (!(a & (a - 1))) return n + 1;
    }
  }

  // Find max a s.t. T::f(args...) returns true,
  // when called for the partition of [a, b) from right to left.
  //   Returns -1 if there is no such a.
  template <class F, class... Args>
  int findLeft(int b, F f, Args &&... args) {
    assert(0 <= b); assert(b <= n);
    if ((T().*f)(args...)) return b;
    if (b == 0) return -1;
    b += n;
    for (int h = logN; h; --h) push((b - 1) >> h);
    for (; ; b >>= 1) if ((b & 1) || b == 2) {
      if ((ts[b - 1].*f)(args...)) {
        for (; b <= n; ) {
          push(b - 1);
          if (!(ts[(b <<= 1) - 1].*f)(args...)) --b;
        }
        return b - n - 1;
      }
      --b;
      if (!(b & (b - 1))) return -1;
    }
  }
};

////////////////////////////////////////////////////////////////////////////////


using Mint = ModLong61;

struct Node {
  Mint pw, sum;
  Mint f, g;
  Mint lz;
  Node() : pw(1), sum(0), f(0), g(0) {}
  Node(Mint val) : pw(BASE), sum(1), f(val), g(val) {}
  void push(Node &l, Node &r) {
    if (lz) {
      l.add(lz);
      r.add(lz);
      lz = 0;
    }
  }
  void pull(const Node &l, const Node &r) {
    pw = l.pw * r.pw;
    sum = l.sum + r.sum;
    f = l.f + l.pw * r.f;
    g = l.g * r.pw + r.g;
  }
  void add(Mint val) {
    f += sum * val;
    g += sum * val;
    lz += val;
  }
};


int N, Q;
Int K, B;
vector<Int> A;

int main() {
  for (; ~scanf("%d%d%lld%lld", &N, &Q, &K, &B); ) {
    A.resize(N);
    for (int i = 0; i < N; ++i) {
      scanf("%lld", &A[i]);
    }
    
    vector<Mint> tar(N + 1, 0);
    {
      Mint pw = 1;
      for (int i = 0; i < N; ++i) {
        tar[i + 1] = tar[i] + pw * (K * (i + 1) + B);
        pw *= BASE;
      }
    }
    
    SegmentTreeRange<Node> seg(A);
    for (; Q--; ) {
      int O;
      scanf("%d", &O);
      if (O == 1) {
        int L, R;
        Int V;
        scanf("%d%d%lld", &L, &R, &V);
        --L;
        seg.ch(L, R, &Node::add, V);
      } else if (O == 2) {
        int I;
        scanf("%d", &I);
        --I;
        int lo = 0, hi = min(I, N - 1 - I) + 1;
        for (; lo + 1 < hi; ) {
          const int mid = (lo + hi) / 2;
          const auto g = seg.get(I - mid, I).g;
          const auto f = seg.get(I + 1, I + 1 + mid).f;
          ((f - g == tar[mid]) ? lo : hi) = mid;
        }
        printf("%d\n", lo);
      } else {
        assert(false);
      }
    }
  }
  return 0;
}