88 lines
4.0 KiB
C++
88 lines
4.0 KiB
C++
// Copyright 2010-2024 Google LLC
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
// The header defines an interface for functions taking and returning an int64_t
|
|
// and supporting range queries over their domain and codomain.
|
|
|
|
#ifndef OR_TOOLS_UTIL_RANGE_QUERY_FUNCTION_H_
|
|
#define OR_TOOLS_UTIL_RANGE_QUERY_FUNCTION_H_
|
|
|
|
#include <cstdint>
|
|
#include <functional>
|
|
|
|
namespace operations_research {
|
|
// RangeIntToIntFunction is an interface to int64_t->int64_t functions
|
|
// supporting fast answer to range queries about their domain/codomain.
|
|
class RangeIntToIntFunction {
|
|
public:
|
|
virtual ~RangeIntToIntFunction() = default;
|
|
|
|
// Suppose f is the abstract underlying function.
|
|
// Returns f(argument).
|
|
// TODO(user): Rename to Run
|
|
virtual int64_t Query(int64_t argument) const = 0;
|
|
// Returns min_x f(x), where x is in [from, to).
|
|
virtual int64_t RangeMin(int64_t from, int64_t to) const = 0;
|
|
// Returns max_x f(x), where x is in [from, to).
|
|
virtual int64_t RangeMax(int64_t from, int64_t to) const = 0;
|
|
// Returns the first x from [range_begin, range_end) for which f(x) is in
|
|
// [interval_begin, interval_end), or range_end if there is no such x.
|
|
virtual int64_t RangeFirstInsideInterval(int64_t range_begin,
|
|
int64_t range_end,
|
|
int64_t interval_begin,
|
|
int64_t interval_end) const = 0;
|
|
// Returns the last x from [range_begin, range_end) for which f(x) is in
|
|
// [interval_begin, interval_end), or range_begin-1 if there is no such x.
|
|
virtual int64_t RangeLastInsideInterval(int64_t range_begin,
|
|
int64_t range_end,
|
|
int64_t interval_begin,
|
|
int64_t interval_end) const = 0;
|
|
};
|
|
|
|
// RangeMinMaxIndexFunction is different from RangeIntToIntFunction in two ways:
|
|
//
|
|
// 1. It does not support codomain or value queries.
|
|
//
|
|
// 2. For domain queries it returns an argument where the minimum/maximum is
|
|
// attained, rather than the minimum/maximum value.
|
|
class RangeMinMaxIndexFunction {
|
|
public:
|
|
virtual ~RangeMinMaxIndexFunction() = default;
|
|
// Suppose f is the abstract underlying function.
|
|
// Returns an x from [from, to), such that f(x) => f(y) for every y from
|
|
// [from, to).
|
|
virtual int64_t RangeMaxArgument(int64_t from, int64_t to) const = 0;
|
|
// Returns an x from [from, to), such that f(x) <= f(y) for every y from
|
|
// [from, to).
|
|
virtual int64_t RangeMinArgument(int64_t from, int64_t to) const = 0;
|
|
};
|
|
|
|
// A copy of f is going to be stored in the returned object, so its closure
|
|
// should remain intact as long as the returned object is being used.
|
|
RangeIntToIntFunction* MakeBareIntToIntFunction(
|
|
std::function<int64_t(int64_t)> f);
|
|
// It is assumed that f is defined over the interval [domain_start, domain_end).
|
|
// The function scans f once and it is safe to destroy f and its closure after
|
|
// MakeCachedIntToIntFunction returns.
|
|
RangeIntToIntFunction* MakeCachedIntToIntFunction(
|
|
const std::function<int64_t(int64_t)>& f, int64_t domain_start,
|
|
int64_t domain_end);
|
|
// It is safe to destroy the first argument and its closure after
|
|
// MakeCachedRangeMinMaxIndexFunction returns.
|
|
RangeMinMaxIndexFunction* MakeCachedRangeMinMaxIndexFunction(
|
|
const std::function<int64_t(int64_t)>& f, int64_t domain_start,
|
|
int64_t domain_end);
|
|
} // namespace operations_research
|
|
|
|
#endif // OR_TOOLS_UTIL_RANGE_QUERY_FUNCTION_H_
|