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

#define endl "\n"
using ll = long long;
using ull = unsigned long long;
using i128 = __int128;
constexpr ull P = 1e18 + 9;
constexpr ull B = 29996224275833;
constexpr int N = 2e5 + 5, M = 1e9;
ull base[N];
struct Info {
    ull v1, v2;
    int len;
}tr[N << 2];

Info merge(Info p, Info q) {
    Info res{};
    res.v1 = ((i128)p.v1 * base[q.len] % P + q.v1) % P;
    res.v2 = ((i128)q.v2 * base[p.len] % P + p.v2) % P;
    res.len = p.len + q.len;
    return res;
}

void modify(int u, int l, int r, int x, int v) {
    if (l == r) {
        tr[u].v1 = v;
        tr[u].v2 = 2 * M - v;
        tr[u].len = 1;
        return;
    }
    int mid = l + r >> 1;
    if (mid >= x) {
        modify(u << 1, l, mid, x, v);
    } else {
        modify(u << 1 | 1, mid + 1, r, x, v);
    }
    tr[u] = merge(tr[u << 1], tr[u << 1 | 1]);
}

Info query(int u, int l, int r, int L, int R) {
    if (L <= l && R >= r) {
        return tr[u];
    }
    int mid = l + r >> 1;
    Info lf{}, rf{};
    if (mid >= L) {
        lf = query(u << 1, l, mid, L, R);
    }
    if (mid < R) {
        rf = query(u << 1 | 1, mid + 1, r, L, R);
    }
    Info res = merge(lf, rf);
    return res;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    int n, q, k, b;
    cin >> n >> q >> k >> b;
    vector<int> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }    

    base[0] = 1;
    for (int i = 1; i <= n; i++) {
        base[i] = (i128) base[i - 1] * B % P;
    }

    vector<ll> dif(n - 1);
    for (int i = 0; i < n - 1; i++) {
        dif[i] = a[i + 1] - a[i] + M;
        modify(1, 0, n - 1, i, dif[i]);
    }

    vector<ull> sum(n + 1);
    sum[0] = k;
    for (int i = 1; i <= n; i++) {
        sum[i] = ((i128) sum[i - 1] * B % P + k) % P;
    }

    while (q--) {
        int op;
        cin >> op;
        if (op == 1) {
            int l, r, v;
            cin >> l >> r >> v;
            l--, r--;
            if (l != 0) {
                dif[l - 1] += v;
                modify(1, 0, n - 1, l - 1, dif[l - 1]);
            }
            if (r != n - 1) {
                dif[r] -= v;
                modify(1, 0, n - 1, r, dif[r]);
            }
        } else {
            int x;
            cin >> x;
            x--;
            if (x == 0 || x == n - 1) {
                cout << 0 << endl;
            } else {
                if (dif[x] != 2 * M - dif[x - 1] + k + b) {
                    cout << 0 << endl;
                    continue;
                }
                int l = 1, r = min(x - 1, n - 2 - x);
                while (l < r) {
                    int mid = l + r + 1 >> 1;
                    if (query(1, 0, n - 1, x - 1 - mid, x - 2).v1 == query(1, 0, n - 1, x + 1, x + 1 + mid).v2 + sum[mid - 1]) l = mid;
                    else r = mid - 1;
                }
                if (l != r || (l == 1 && query(1, 0, n - 1, x - 2, x - 2).v1 != query(1, 0, n - 1, x + 1, x + 1).v2 + k)) {
                    l = 0;
                }
                cout << l + 1 << endl;
            }
        }
    }

    return 0;
}