#include <bits/stdc++.h>

#define int long long

#define pii pair<int, int>

#define x1 x1228
#define y1 y1228

#define left left228
#define right right228

#define pb push_back
#define eb emplace_back

#define mp make_pair

#define ff first
#define ss second

#define matr vector<vector<int> >

#define all(x) x.begin(), x.end()


using namespace std;
typedef long long ll;
typedef long double ld;

const int maxn = 3e5 + 7, mod = 1e9 + 7, inf = 1e18, MAXN = 1e6 + 7;
const double eps = 1e-9;
mt19937 rnd(time(0));
int n, m;
vector<int> kek[maxn];
int cnt[maxn];

int get(int id, int l1, int r1) {
    int l = lower_bound(all(kek[id]), l1) - kek[id].begin();
    int r = upper_bound(all(kek[id]), r1) - kek[id].begin() - 1;
    return r - l + 1;
}

void solve() {
    cin >> n >> m;
    vector<int> have;
    for (int i = 0; i < n; ++i) {
        cin >> cnt[i];
        cnt[i] -= i;
        have.pb(cnt[i]);
    }
    sort(all(have));
    have.erase(unique(all(have)), have.end());
    for (int i = 0; i < n; ++i) {
        int id = lower_bound(all(have), cnt[i]) - have.begin();
        kek[id].pb(i);
    }
    for (int i = 0; i < m; ++i) {
        int l, r, x; cin >> l >> r >> x, --l, --r;
        int p = x - l;
        int id = lower_bound(all(have), p) - have.begin();
        if (id >= 0 && id < have.size() && have[id] == p) {
            cout << get(id, l, r) << '\n';
        } else {
            cout << "0\n";
        }
    }
}

signed main() {
#ifdef LOCAL
    freopen("TASK.in", "r", stdin);
    freopen("TASK.out", "w", stdout);
#else

#endif // LOCAL
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.precision(20);
    cout << fixed;
    int t = 1;
    for (int i = 0; i < t; ++i)
        solve();
    return 0;
}