#include <bits/stdc++.h>
#define int long long
#define endl '\n'
using namespace std;
const int N = 3e5 + 5;
int n, t;
int d;
int c[N];
vector < pair < int, int > > queries[N];
int ans[N];
struct Node
{
int val;
int lazy;
};
struct Seggy
{
Node tree[4 * N];
void push(int node, int l, int r)
{
if (tree[node].lazy == 0)
{
return;
}
int mid = (l + r) / 2;
tree[2 * node].val += (mid - l + 1) * tree[node].lazy;
tree[2 * node + 1].val += (r - mid) * tree[node].lazy;
tree[2 * node].lazy += tree[node].lazy;
tree[2 * node + 1].lazy += tree[node].lazy;
tree[node].lazy = 0;
}
void update(int node, int l, int r, int ql, int qr, int val)
{
if (l > qr || r < ql)
{
return;
}
if (ql <= l && r <= qr)
{
tree[node].val += (r - l + 1) * val;
tree[node].lazy += val;
return;
}
int mid = (l + r) / 2;
push(node, l, r);
update(2 * node, l, mid, ql, qr, val);
update(2 * node + 1, mid + 1, r, ql, qr, val);
tree[node].val = tree[2 * node].val + tree[2 * node + 1].val;
}
int query(int node, int l, int r, int ql, int qr)
{
if (l > qr || r < ql)
{
return 0;
}
if (ql <= l && r <= qr)
{
return tree[node].val;
}
int mid = (l + r) / 2;
push(node, l, r);
return query(2 * node, l, mid, ql, qr) + query(2 * node + 1, mid + 1, r, ql, qr);
}
};
Seggy segment;
signed main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cin >> n >> d;
for (int i = 1; i <= n; i++)
{
cin >> c[i];
}
cin >> t;
for (int i = 1; i <= t; i++)
{
int l, r;
cin >> l >> r;
queries[r].push_back({l, i});
}
stack < int > st;
for (int i = 1; i <= n; i++)
{
int r = i;
while (!st.empty())
{
int a = c[r - 1] - segment.query(1, 1, n, r - 1, r - 1) * d;
int b = c[r] - segment.query(1, 1, n, r, r) * d;
if (a <= b)
{
break;
}
int more = (a - b - 1) / d + 1;
segment.update(1, 1, n, st.top(), r - 1, more);
r = st.top();
st.pop();
}
st.push(r);
for (auto [l, id] : queries[i])
{
if (c[l] - segment.query(1, 1, n, l, l) * d < 0)
{
ans[id] = -1;
}
else
{
ans[id] = segment.query(1, 1, n, l, i);
}
}
}
for (int i = 1; i <= t; i++)
{
cout << ans[i] << endl;
}
return 0;
}
