atcoder/fenwicktree.hpp

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• Last update: 2020-10-30 19:21:58+09:00
• Include: #include "atcoder/fenwicktree.hpp"
• Link: https://en.wikipedia.org/wiki/Fenwick_tree

Depends on

• atcoder/internal_type_traits.hpp

Code

#ifndef ATCODER_FENWICKTREE_HPP
#define ATCODER_FENWICKTREE_HPP 1

#include "./internal_type_traits.hpp"
#include <cassert>
#include <vector>

namespace atcoder {

	// Reference: https://en.wikipedia.org/wiki/Fenwick_tree
	template <class T> struct fenwick_tree {
		using U = internal::to_unsigned_t<T>;

	public:
		fenwick_tree() : _n(0) {}
		fenwick_tree(int n) : _n(n), data(n) {}

		void add(int p, T x) {
			assert(0 <= p && p < _n);
			p++;
			while (p <= _n) {
				data[p - 1] += U(x);
				p += p & -p;
			}
		}

		T sum(int l, int r) {
			assert(0 <= l && l <= r && r <= _n);
			return sum(r) - sum(l);
		}

	private:
		int _n;
		std::vector<U> data;

		U sum(int r) {
			U s = 0;
			while (r > 0) {
				s += data[r - 1];
				r -= r & -r;
			}
			return s;
		}
	};

}  // namespace atcoder

#endif  // ATCODER_FENWICKTREE_HPP

#line 1 "atcoder/fenwicktree.hpp"



#line 1 "atcoder/internal_type_traits.hpp"



#include <cassert>
#include <numeric>
#include <type_traits>

namespace atcoder {

	namespace internal {

#ifndef _MSC_VER
		template <class T>
		using is_signed_int128 =
		    typename std::conditional<std::is_same<T, __int128_t>::value || std::is_same<T, __int128>::value,
		                              std::true_type, std::false_type>::type;

		template <class T>
		using is_unsigned_int128 =
		    typename std::conditional<std::is_same<T, __uint128_t>::value || std::is_same<T, unsigned __int128>::value,
		                              std::true_type, std::false_type>::type;

		template <class T>
		using make_unsigned_int128 =
		    typename std::conditional<std::is_same<T, __int128_t>::value, __uint128_t, unsigned __int128>;

		template <class T>
		using is_integral = typename std::conditional<std::is_integral<T>::value || is_signed_int128<T>::value ||
		                                                  is_unsigned_int128<T>::value,
		                                              std::true_type, std::false_type>::type;

		template <class T>
		using is_signed_int =
		    typename std::conditional<(is_integral<T>::value && std::is_signed<T>::value) || is_signed_int128<T>::value,
		                              std::true_type, std::false_type>::type;

		template <class T>
		using is_unsigned_int = typename std::conditional<(is_integral<T>::value && std::is_unsigned<T>::value) ||
		                                                      is_unsigned_int128<T>::value,
		                                                  std::true_type, std::false_type>::type;

		template <class T>
		using to_unsigned =
		    typename std::conditional<is_signed_int128<T>::value, make_unsigned_int128<T>,
		                              typename std::conditional<std::is_signed<T>::value, std::make_unsigned<T>,
		                                                        std::common_type<T>>::type>::type;

#else

		template <class T> using is_integral = typename std::is_integral<T>;

		template <class T>
		using is_signed_int = typename std::conditional<is_integral<T>::value && std::is_signed<T>::value,
		                                                std::true_type, std::false_type>::type;

		template <class T>
		using is_unsigned_int = typename std::conditional<is_integral<T>::value && std::is_unsigned<T>::value,
		                                                  std::true_type, std::false_type>::type;

		template <class T>
		using to_unsigned =
		    typename std::conditional<is_signed_int<T>::value, std::make_unsigned<T>, std::common_type<T>>::type;

#endif

		template <class T> using is_signed_int_t = std::enable_if_t<is_signed_int<T>::value>;

		template <class T> using is_unsigned_int_t = std::enable_if_t<is_unsigned_int<T>::value>;

		template <class T> using to_unsigned_t = typename to_unsigned<T>::type;

	}  // namespace internal

}  // namespace atcoder


#line 6 "atcoder/fenwicktree.hpp"
#include <vector>

namespace atcoder {

	// Reference: https://en.wikipedia.org/wiki/Fenwick_tree
	template <class T> struct fenwick_tree {
		using U = internal::to_unsigned_t<T>;

	public:
		fenwick_tree() : _n(0) {}
		fenwick_tree(int n) : _n(n), data(n) {}

		void add(int p, T x) {
			assert(0 <= p && p < _n);
			p++;
			while (p <= _n) {
				data[p - 1] += U(x);
				p += p & -p;
			}
		}

		T sum(int l, int r) {
			assert(0 <= l && l <= r && r <= _n);
			return sum(r) - sum(l);
		}

	private:
		int _n;
		std::vector<U> data;

		U sum(int r) {
			U s = 0;
			while (r > 0) {
				s += data[r - 1];
				r -= r & -r;
			}
			return s;
		}
	};

}  // namespace atcoder

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