#include <bits/stdc++.h>

using namespace std;

const int N = 200'000 + 10;
int n, q, k, b;
int a[N];

int d[N];
const int base = 100'000'007,
          M = 1'000'000'007;
int pw[N];
struct Node { 
  int fwd, bwd;
  Node() : fwd(0), bwd(0) {}
  Node(int fwd, int bwd) : fwd(fwd), bwd(bwd) {}
} f[N << 2];
void build(int s, int l, int r) { 
  if (l == r) { 
    f[s].fwd = f[s].bwd = (d[l] + M) % M;
    return;
  }
  int mid = (l + r) >> 1;
  build(s << 1, l, mid); build(s << 1 | 1, mid + 1, r);
  f[s].fwd = (1ll * f[s << 1].fwd * pw[r - mid] % M + f[s << 1 | 1].fwd) % M;
  f[s].bwd = (1ll * f[s << 1 | 1].bwd * pw[mid - l + 1] % M + f[s << 1].bwd) % M; 
}
void update(int s, int l, int r, int p, int x) { 
  if (p < l || p > r) return;
  if (l == r) { 
    f[s].fwd = (f[s].fwd + x + M) % M;
    f[s].bwd = (f[s].bwd + x + M) % M;
    return;
  }
  int mid = (l + r) >> 1;
  update(s << 1, l, mid, p, x); update(s << 1 | 1, mid + 1, r, p, x);
  f[s].fwd = (1ll * f[s << 1].fwd * pw[r - mid] % M + f[s << 1 | 1].fwd) % M;
  f[s].bwd = (1ll * f[s << 1 | 1].bwd * pw[mid - l + 1] % M + f[s << 1].bwd) % M; 
}
Node query(int s, int l, int r, int u, int v) { 
  if (v < l || u > r) return Node();
  if (u <= l && r <= v) return f[s];
  int mid = (l + r) >> 1;
  
  if (mid > v) return query(s << 1, l, mid, u, v);
  if (mid < u) return query(s << 1 | 1, mid + 1, r, u, v);

  Node lt = query(s << 1, l, mid, u, v), rt = query(s << 1 | 1, mid + 1, r, u, v);
  Node ret;
  ret.fwd = (1ll * lt.fwd * pw[min(r, v) - mid] % M + rt.fwd) % M;
  ret.bwd = (1ll * rt.bwd * pw[mid - max(l, u) + 1] % M + lt.bwd) % M;
  return ret;
}
int answer[N];

int32_t main() { 
  cin.tie(0)->sync_with_stdio(0);

  cin >> n >> q >> k >> b;
  for (int i = 1; i <= n; ++i) cin >> a[i];

  pw[0] = 1;
  for (int i = 1; i <= n; ++i) pw[i] = 1ll * pw[i - 1] * base % M;
  for (int i = 2; i <= n; ++i) d[i] = a[i] - a[i - 1];
  build(1, 1, n);

  answer[1] = k;
  for (int i = 2; i <= n; ++i) answer[i] = (1ll * answer[i - 1] * base % M + k) % M;
  
  while (q--) { 
    int type; cin >> type;

    if (type == 1) { 
      int l, r, x; cin >> l >> r >> x;
      update(1, 1, n, l, x);
      update(1, 1, n, r + 1, -x);
    } else { 
      int i; cin >> i;

      if (i == 1 || i == n || (query(1, 1, n, i + 1, i + 1).fwd + query(1, 1, n, i, i).bwd) % M != (k + b + M) % M) { 
        cout << 0 << "\n"; continue; 
      }

      int l = 2, r = min(i, n - i), ret = 1;
      while (l <= r) { 
        int mid = (l + r) >> 1;
        int sum = (query(1, 1, n, i + 2, i + mid).fwd + query(1, 1, n, i - mid + 1, i - 1).bwd) % M;
        if (sum == answer[mid - 1]) l = (ret = mid) + 1;
        else r = mid - 1;
      }

      cout << ret << "\n";
    }
  }
}