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| 1 | +#include <bits/stdc++.h> |
| 2 | +#define ll long long |
| 3 | +using namespace std; |
| 4 | + |
| 5 | +vector<ll> a; |
| 6 | + |
| 7 | +struct node { |
| 8 | + vector<ll> vec; |
| 9 | + node *left, *right; |
| 10 | + |
| 11 | + node() { |
| 12 | + left = right = nullptr; |
| 13 | + } |
| 14 | +}; |
| 15 | + |
| 16 | +node* build(ll l, ll r) { |
| 17 | + node* newnode = new node(); |
| 18 | + if (l == r) { |
| 19 | + newnode->vec.push_back(a[l]); |
| 20 | + return newnode; |
| 21 | + } |
| 22 | + ll m = l+(r-l)/2; |
| 23 | + newnode->left = build(l,m); |
| 24 | + newnode->right = build(m+1,r); |
| 25 | + ll i = 0, j = 0; |
| 26 | + vector<ll> &vec_l = newnode->left->vec, &vec_r = newnode->right->vec;; |
| 27 | + while (i < vec_l.size() and j < vec_r.size()) { |
| 28 | + if (vec_l[i] < vec_r[j]) { |
| 29 | + newnode->vec.push_back(vec_l[i]); |
| 30 | + i++; |
| 31 | + } |
| 32 | + else { |
| 33 | + newnode->vec.push_back(vec_r[j]); |
| 34 | + j++; |
| 35 | + } |
| 36 | + } |
| 37 | + |
| 38 | + while (i < vec_l.size()) { |
| 39 | + newnode->vec.push_back(vec_l[i]); |
| 40 | + i++; |
| 41 | + } |
| 42 | + |
| 43 | + while (j < vec_r.size()) { |
| 44 | + newnode->vec.push_back(vec_r[j]); |
| 45 | + j++; |
| 46 | + } |
| 47 | + |
| 48 | + return newnode; |
| 49 | +} |
| 50 | + |
| 51 | +// query to find number of elements less than k in [ql,qr] |
| 52 | +ll query(node* root, ll ql, ll qr, ll l, ll r, ll &k) { |
| 53 | + if (ql > r or qr < l or l > r) { |
| 54 | + return 0; |
| 55 | + } |
| 56 | + if (ql <= l and r <= qr) { |
| 57 | + return lower_bound(root->vec.begin(), root->vec.end(),k) - root->vec.begin(); |
| 58 | + } |
| 59 | + ll m = l+(r-l)/2; |
| 60 | + return query(root->left, ql, qr, l, m, k) + query(root->right, ql, qr, m+1, r, k); |
| 61 | +} |
| 62 | + |
| 63 | +int main() { |
| 64 | + ll i,n,k,q,l,r; |
| 65 | + cin >> n; |
| 66 | + a.resize(n); |
| 67 | + for (i = 0; i < n; i++) { |
| 68 | + cin >> a[i]; |
| 69 | + } |
| 70 | + node* root = build(0,n-1); |
| 71 | + cin >> q; |
| 72 | + while (q--) { |
| 73 | + cin >> l >> r >> k; |
| 74 | + l--;r--; |
| 75 | + cout << query(root,l,r,0,n-1,k) << endl; |
| 76 | + } |
| 77 | +} |
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