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#define PROBLEM "https://judge.yosupo.jp/problem/static_range_inversions_query" #include <bits/stdc++.h> #include "misc/mo.hpp" #include "data_structure/fenwick_tree.hpp" int main() { int N, Q; std::cin >> N >> Q; std::vector<int> A(N); for (int i = 0; i < N; i++) std::cin >> A[i]; std::vector<int> L(Q), R(Q); for (int i = 0; i < Q; i++) std::cin >> L[i] >> R[i]; auto B = A; std::sort(B.begin(), B.end()); B.erase(std::unique(B.begin(), B.end()), B.end()); for (auto &&e : A) e = std::lower_bound(B.begin(), B.end(), e) - B.begin(); const int M = (int)B.size(); FenwickTree<long long> fen(M); std::vector<long long> ans(Q); long long cur = 0; auto add_left = [&](int i) { cur += fen.sum(A[i]); fen.add(A[i], 1); }; auto add_right = [&](int i) { cur += fen.sum(A[i] + 1, M); fen.add(A[i], 1); }; auto del_left = [&](int i) { cur -= fen.sum(A[i]); fen.add(A[i], -1); }; auto del_right = [&](int i) { cur -= fen.sum(A[i] + 1, M); fen.add(A[i], -1); }; auto out = [&](int i) { ans[i] = cur; }; mo(N, L, R, add_left, add_right, del_left, del_right, out); for (int i = 0; i < Q; i++) std::cout << ans[i] << '\n'; return 0; }
#line 1 "verify/lc_data_structure/lc_static_range_inversions_query.test.cpp" #define PROBLEM "https://judge.yosupo.jp/problem/static_range_inversions_query" #include <bits/stdc++.h> #line 2 "misc/mo.hpp" // Mo's Algorithm // https://snuke.hatenablog.com/entry/2016/07/01/000000 // complexity: O(N^2/B + QB) // -> O(N sqrt(Q)) (B := N / sqrt(Q)) template <class AddLeft, class AddRight, class DelLeft, class DelRight, class Out> // void mo(const int &n, const std::vector<int> &l, const std::vector<int> &r, // const AddLeft &add_left, const AddRight &add_right, // const DelLeft &del_left, const DelRight &del_right, const Out &out) { const int q = (int)l.size(); if (q == 0) return; // normal // const int bucket_size = std::max(1.0, n / std::max(1.0, sqrt(q))); // speed up by https://nyaannyaan.github.io/library/misc/mo.hpp const int bucket_size = std::max(1.0, n / std::max(1.0, sqrt(2.0 * q / 3.0))); std::vector<int> ind(q), lbs(q); // reduce the number of divisions by memoization for (int i = 0; i < q; i++) lbs[i] = l[i] / bucket_size; std::iota(ind.begin(), ind.end(), 0); std::sort(ind.begin(), ind.end(), [&](int i, int j) { if (lbs[i] != lbs[j]) return l[i] < l[j]; return (lbs[i] & 1) ? r[i] > r[j] : r[i] < r[j]; }); // initialize with [ l[ind[0]], l[ind[0]] ) instead of [0, 0) int now_l = l[ind[0]], now_r = now_l; for (auto &&i : ind) { while (now_l > l[i]) add_left(--now_l); while (now_r < r[i]) add_right(now_r++); while (now_l < l[i]) del_left(now_l++); while (now_r > r[i]) del_right(--now_r); out(i); } } template <class Add, class Del, class Out> // void mo(const int n, const std::vector<int> &l, const std::vector<int> &r, // const Add &add, const Del &del, const Out &out) { mo(n, l, r, add, add, del, del, out); } #line 2 "data_structure/fenwick_tree.hpp" template <class T> struct FenwickTree { int n; std::vector<T> seg; FenwickTree() : n(0) {} FenwickTree(int n) : n(n), seg(n + 1, 0) {} FenwickTree(std::vector<T>& arr) { n = int(arr.size()); seg.resize(n + 1); for (int i = 0; i < n; i++) add(i, arr[i]); } // A[i] += x void add(int i, const T& x) { assert(0 <= i and i < n); i++; // 1-indexed while (i <= n) { seg[i] += x; i += i & -i; } } // A[0] + ... + A[i - 1] T sum(int i) const { assert(0 <= i and i <= n); T s = T(0); while (i > 0) { s += seg[i]; i -= i & -i; } return s; } // A[a] + ... + A[b - 1] T sum(int a, int b) const { assert(0 <= a and a <= b and b <= n); return sum(b) - sum(a); } // return A[i] T get(int i) const { return sum(i, i + 1); } // A[i] = x void set(int i, const T x) { add(i, x - get(i)); } // output friend std::ostream& operator<<(std::ostream& os, const FenwickTree& fen) { for (int i = 0; i < fen.n; i++) os << fen.get(i) << " \n"[i == fen.n - 1]; return os; } }; #line 7 "verify/lc_data_structure/lc_static_range_inversions_query.test.cpp" int main() { int N, Q; std::cin >> N >> Q; std::vector<int> A(N); for (int i = 0; i < N; i++) std::cin >> A[i]; std::vector<int> L(Q), R(Q); for (int i = 0; i < Q; i++) std::cin >> L[i] >> R[i]; auto B = A; std::sort(B.begin(), B.end()); B.erase(std::unique(B.begin(), B.end()), B.end()); for (auto &&e : A) e = std::lower_bound(B.begin(), B.end(), e) - B.begin(); const int M = (int)B.size(); FenwickTree<long long> fen(M); std::vector<long long> ans(Q); long long cur = 0; auto add_left = [&](int i) { cur += fen.sum(A[i]); fen.add(A[i], 1); }; auto add_right = [&](int i) { cur += fen.sum(A[i] + 1, M); fen.add(A[i], 1); }; auto del_left = [&](int i) { cur -= fen.sum(A[i]); fen.add(A[i], -1); }; auto del_right = [&](int i) { cur -= fen.sum(A[i] + 1, M); fen.add(A[i], -1); }; auto out = [&](int i) { ans[i] = cur; }; mo(N, L, R, add_left, add_right, del_left, del_right, out); for (int i = 0; i < Q; i++) std::cout << ans[i] << '\n'; return 0; }