Test/SparseTable.test.cpp

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• Last update: 2021-03-12 18:03:59+09:00
• Problem: https://judge.yosupo.jp/problem/staticrmq

Depends on

• Sparse Table (DataStructure/SparseTable.hpp)

Code

#define PROBLEM "https://judge.yosupo.jp/problem/staticrmq"

#include "DataStructure/SparseTable.hpp"

#include <cstdio>
#include <algorithm>
#include <vector>

int main() {
	int N, Q;
	scanf("%d %d", &N, &Q);
	
	std::vector<int> A(N);
	for (int i = 0; i < N; ++i) scanf("%d", &A[i]);
	
	SparseTable<int> st(A.begin(), A.end(), [](int x, int y) {
		return std::min(x, y);
	});
	while (Q--) {
		int l, r;
		scanf("%d %d", &l, &r);
		printf("%d\n", st.fold(l, r));
	}
}

#line 1 "Test/SparseTable.test.cpp"
#define PROBLEM "https://judge.yosupo.jp/problem/staticrmq"

#line 1 "DataStructure/SparseTable.hpp"



#include <vector>
#include <cassert>
#include <functional>
#include <cstdint>

/**
 * @brief https://tkmst201.github.io/Library/DataStructure/SparseTable.hpp
 */
template<typename T>
struct SparseTable {
public:
	using value_type = T;
	using const_reference = const value_type &;
	using size_type = std::size_t;
	using F = std::function<value_type (const_reference, const_reference)>;
	
private:
	F f;
	std::vector<std::vector<value_type>> table;
	std::vector<std::uint8_t> log_table;
	
public:
	template<class InputIterator>
	SparseTable(InputIterator first, InputIterator last, const F & f) : f(f) {
		table.emplace_back(first, last);
		build();
	}
	
	size_type size() const noexcept {
		return table.empty() ? 0 : table.front().size();
	}
	
	value_type fold(size_type l, size_type r) const noexcept {
		assert(l < r);
		assert(r <= size());
		const size_type k = log_table[r - l];
		return f(table[k][l], table[k][r - (1 << k)]);
	}
	
private:
	void build() {
		log_table.reserve(size() + 1);
		log_table.emplace_back(0);
		log_table.emplace_back(0);
		for (size_type i = 2; i <= size(); ++i) log_table.emplace_back(log_table[i >> 1] + 1);
		
		table.reserve(log_table[size()] + 1);
		for (size_type i = 1; i <= log_table[size()]; ++i) {
			table.emplace_back();
			table[i].reserve(size() - (1 << i) + 1);
			for (size_type j = 0; j + (1 << i) <= size(); ++j) {
				table[i].emplace_back(f(table[i - 1][j], table[i - 1][j + (1 << (i - 1))]));
			}
		}
	}
};


#line 4 "Test/SparseTable.test.cpp"

#include <cstdio>
#include <algorithm>
#line 8 "Test/SparseTable.test.cpp"

int main() {
	int N, Q;
	scanf("%d %d", &N, &Q);
	
	std::vector<int> A(N);
	for (int i = 0; i < N; ++i) scanf("%d", &A[i]);
	
	SparseTable<int> st(A.begin(), A.end(), [](int x, int y) {
		return std::min(x, y);
	});
	while (Q--) {
		int l, r;
		scanf("%d %d", &l, &r);
		printf("%d\n", st.fold(l, r));
	}
}

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