Question

任务说明

interval_map<K,V>是一种数据结构，可以有效地将K类型的键的间隔与V类型的值相关联。您的任务是实现此数据结构的assign成员函数，如下所述。

interval_map<K, V>在std::map之上实现。如果您不确定std::map提供的功能，提供的功能以及提供的保证，请在此处提供C ++标准的摘录。（最后）

std::map中的每个键值对（k，v）表示值v与std::map中从k（包括）到下一个键（不包括）的间隔相关联

示例：std::map (0,'A'), (3,'B'), (5,'A')代表映射


0->'A'

1->'A'

2->'A'

3->'B'

4->'B'

5->'A'

6->'A'

7->'A'


...一直到numeric_limits<int>::max()

std::map中的表示形式必须是规范的，即连续的映射条目不得具有相同的值：不允许..., (0,'A'), (3,'A'), ...。最初，K的整个范围都与给定的初始值相关联，并传递给interval_map数据结构的构造函数。

这是我对assign()的实现：（其余代码默认情况下）。

#include <map>
#include <limits>

template<typename K, typename V>
class interval_map {
    std::map<K,V> m_map;

public:
  // constructor associates whole range of K with val by inserting (K_min, val)
  // into the map
  interval_map( V const& val) {
      m_map.insert(m_map.end(),std::make_pair(std::numeric_limits<K>::lowest(),val));
  }

  // Assign value val to interval [keyBegin, keyEnd).
  // Overwrite previous values in this interval.
  // Conforming to the C++ Standard Library conventions, the interval
  // includes keyBegin, but excludes keyEnd.
  // If !( keyBegin < keyEnd ), this designates an empty interval,
  // and assign must do nothing.
  void assign( K const& keyBegin, K const& keyEnd, V const& val ) {

        // insert code here   
        if (!(keyBegin < keyEnd)) return;

        std::pair<K,V> beginExtra;
        std::pair<K,V> endExtra;
        bool beginHasExtra = false;
        bool endHasExtra = false;

        typename std::map<K,V>::iterator itBegin;
        itBegin = m_map.lower_bound(keyBegin);
        if ( itBegin!=m_map.end() && keyBegin < itBegin->first ) {
            if (itBegin != m_map.begin()) {
                beginHasExtra = true;
                --itBegin;
                beginExtra = std::make_pair(itBegin->first, itBegin->second);
            }
            // openRange for erase is prevIterator
            // insert (prevIterator->first, prevIterator->second) as well!
        }

        typename std::map<K,V>::iterator itEnd;
        itEnd = m_map.lower_bound(keyEnd);
        if ( itEnd!=m_map.end() && keyEnd < itEnd->first ) {
            endHasExtra = true;
            typename std::map<K,V>::iterator extraIt = itEnd;
            --extraIt;
            endExtra = std::make_pair(keyEnd, extraIt->second);
            // closeRange for erase is this iterator
            // insert (keyEnd, prevIterator->second) as well!
        }

        // 4 canonical conflicts:
        //   beginExtra w/ mid
        //   before-mid w/ mid (beginHasExtra==false)
        //   mid w/ endExtra
        //   mid w/ after-mid (endHasExtra==false)

        bool insertMid = true;
        if (beginHasExtra) {
            if (beginExtra.second == val)
                insertMid = false;
        } else {
            if (itBegin != m_map.begin()) {
                typename std::map<K,V>::iterator beforeMid = itBegin;
                --beforeMid;
                if (beforeMid->second == val)
                    insertMid = false;
            }
        }


        if (endHasExtra) {
            if ( (insertMid && endExtra.second == val) || (!insertMid && endExtra.second == beginExtra.second) )
                endHasExtra = false;
        } else {
            if ( (insertMid && itEnd!=m_map.end() && itEnd->second == val) || (!insertMid && itEnd!=m_map.end() && itEnd->second == beginExtra.second) )
                itEnd = m_map.erase(itEnd);
        }

        itBegin = m_map.erase(itBegin, itEnd);
        if (beginHasExtra)
            itBegin = m_map.insert(itBegin, beginExtra);
        if (insertMid)
            itBegin = m_map.insert(itBegin, std::make_pair(keyBegin, val));
        if (endHasExtra)
            m_map.insert(itBegin, endExtra);
  }

  // look-up of the value associated with key
  V const& operator[]( K const& key ) const {
      return ( --m_map.upper_bound(key) )->second;
  }
};

键类型

K


除了可复制和可分配外，还不如通过运营商进行比较<< / li>
受限制，最小值为std :: numeric_limits :: lowest（）

不执行任何其他操作，尤其是没有相等比较或算术运算符


值类型

V


除了可复制和可分配外，还可以通过operator ==
进行相等比较
不执行任何其他操作

============================================= ==============================

此代码在我的本地计算机上运行良好。但是，提交代码后，我得到了You must adhere to the specification of the key and value type given above.，谁能告诉我我做错了什么？我知道我应该为迭代器使用const_iterator，但是错误是在谈论K, V。

============================================= ==============================

The following paragraphs from the final draft of the C++1x ISO standard describe the available 
operations on a std::map container, their effects and their complexity.

23.2.1 General container requirements 

§1 Containers are objects that store other objects. They control allocation and deallocation of 
these objects through constructors, destructors, insert and erase operations.

§6 begin() returns an iterator referring to the first element in the container. end() returns 
an iterator which is the past-the-end value for the container. If the container is empty, 
then begin() == end();

24.2.1 General Iterator Requirements

§1 Iterators are a generalization of pointers that allow a C++ program to work with different 
data structures.

§2 Since iterators are an abstraction of pointers, their semantics is a generalization of most 
of the semantics of pointers in C++. This ensures that every function template that takes 
iterators works as well with regular pointers.

§5 Just as a regular pointer to an array guarantees that there is a pointer value pointing past 
the last element of the array, so for any iterator type there is an iterator value that points 
past the last element of a corresponding sequence. These values are called past-the-end values. 
Values of an iterator i for which the expression *i is defined are called dereferenceable. 
The library never assumes that past-the-end values are dereferenceable. Iterators can also have 
singular values that are not associated with any sequence. [ Example: After the declaration of 
an uninitialized pointer x (as with int* x;), x  must always be assumed to have a singular 
value of a pointer. -end example ] Results of most expressions are undefined for singular 
values; the only exceptions are destroying an iterator that holds a singular value, the 
assignment of a non-singular value to an iterator that holds a singular value, and, for 
iterators that satisfy the DefaultConstructible requirements, using a value-initialized 
iterator as the source of a copy or move operation.

§10 An invalid iterator is an iterator that may be singular. (This definition applies to 
pointers, since pointers are iterators. The effect of dereferencing an iterator that has been 
invalidated is undefined.)

23.2.4 Associative containers

§1 Associative containers provide fast retrieval of data based on keys. The library provides 
four basic kinds of associative containers: set, multiset, map and multimap.

§4 An associative container supports unique keys if it may contain at most one element for each 
key. Otherwise, it supports equivalent keys. The set and map classes support unique keys; the 
multiset and multimap classes support equivalent keys.

§5 For map and multimap the value type is equal to std::pair<const Key, T>. Keys in an 
associative container are immutable.

§6 iterator of an associative container is of the bidirectional iterator category.
(i.e., an iterator i can be incremented and decremented: ++i; --i;)

§9 The insert member functions (see below) shall not affect the validity of iterators and 
references to the container, and the erase members shall invalidate only iterators and 
references to the erased elements.

§10 The fundamental property of iterators of associative containers is that they iterate 
through the containers in the non-descending order of keys where non-descending is defined by 
the comparison that was used to construct them.

Associative container requirements (in addition to general container requirements):

std::pair<iterator, bool> insert(std::pair<const key_type, T> const" t)
Effects: Inserts t if and only if there is no element in the container with key equivalent to 
the key of t. The bool component of the returned pair is true if and only if the insertion 
takes place, and the iterator component of the pair points to the element with key equivalent 
to the key of t.
Complexity: logarithmic

iterator insert(const_iterator p, std::pair<const key_type, T> const" t)
Effects: Inserts t if and only if there is no element with key equivalent to the key of t in 
containers with unique keys. Always returns the iterator pointing to the element with key 
equivalent to the key of t. 
Complexity: logarithmic in general, but amortized constant if t is inserted right before p.

size_type erase(key_type const" k)  
Effects: Erases all elements in the container with key equivalent to k. Returns the number of 
erased elements.
Complexity: log(size of container) + number of elements with key k

iterator erase(const_iterator q) 
Effects: Erases the element pointed to by q. Returns an iterator pointing to the element 
immediately following q prior to the element being erased. If no such element exists, returns 
end().
Complexity: Amortized constant

iterator erase(const_iterator q1, const_iterator q2)
Effects: Erases all the elements in the left-inclusive and right-exclusive range [q1,q2). 
Returns q2.
Complexity: Amortized O(N) where N has the value distance(q1, q2).

void clear() 
Effects: erase(begin(), end())
Post-Condition: empty() returns true
Complexity: linear in size().

iterator find(key_type const" k);
Effects: Returns an iterator pointing to an element with the key equivalent to k, or end() if 
such an element is not found.
Complexity: logarithmic

size_type count(key_type constquot;& k) 
Effects: Returns the number of elements with key equivalent to k
Complexity: log(size of map) + number of elements with key equivalent to k

iterator lower_bound(key_type const" k)
Effects: Returns an iterator pointing to the first element with key not less than k, or end() 
if such an element is not found.
Complexity: logarithmic

iterator upper_bound(key_type const" k)
Effects: Returns an iterator pointing to the first element with key greater than k, or end() 
if such an element is not found.
Complexity: logarithmic

23.4.1 Class template map

§1 A map is an associative container that supports unique keys (contains at most one of each 
key value) and provides for fast retrieval of values of another type T based on the keys. The 
map class supports bidirectional iterators.

23.4.1.2 map element access

T" operator[](const key_type" x);
Effects: If there is no key equivalent to x in the map, inserts value_type(x, T()) into the map. 
Returns: A reference to the mapped_type corresponding to x in *this.
Complexity: logarithmic.

T" at(const key_type" x);
const T" at(const key_type" x) const;
Returns: A reference to the element whose key is equivalent to x.
Throws: An exception object of type out_of_range if no such element is present.
Complexity: logarithmic.

Answer 1

您要求您的类型必须是默认可构造的：

std::pair<K,V> beginExtra;
std::pair<K,V> endExtra;

这可能是投诉的来源。

Answer 2

哦，那令人费解的编程练习，您是否未签署保密协议而不公开...

我不认为错误消息是完全正确的。但是，只有这一小段代码将向您表明您的代码不正确：

interval_map<uint8_t, std::string> moo("A");
moo.assign(1, 15, "B"); 
std::cout << moo[255];

期望值为A，返回值为B。

Answer 3

我可以为Assign（）方法想出的最短的解决方案。

if (not (keyBegin < keyEnd) )
    return;

auto beginLowerBound = m_map.lower_bound(keyBegin);
auto endLowerBound = m_map.lower_bound(keyEnd);

std::optional<std::pair<K,V>> additionalElement;

if (endLowerBound == m_map.end() || keyEnd < endLowerBound->first)
    additionalElement = std::pair(keyEnd, operator[]( keyEnd ));
else if (beginLowerBound == m_map.end() || keyBegin < beginLowerBound->first)
    additionalElement = std::pair(keyEnd, operator[]( keyBegin ));

if (beginLowerBound != m_map.end())
    m_map.erase(beginLowerBound, endLowerBound);

m_map.insert(std::pair(keyBegin, val));

if (additionalElement)
    m_map.insert(additionalElement.value());

Answer 4

就像其他人所说的那样，您的代码中的问题是假设K，V都可以默认构造。当您测试不可默认构造的键类型时，这一点变得很清楚（请参见下面的测试）

'std::pair<K,V>::pair': no appropriate default constructor available

这是我的实现，通过了正确性检查，但未通过运行时复杂性检查。我看不到如何擦除N个键，但保持复杂度O（logN），请考虑以下合法情况：

分配前

'A'.................'B'...百万间隔....'C'...... ....................'A'..

分配新的时间间隔后，覆盖以前的时间间隔：

'A'.........'D'............................... ................................... '一种' ............ ............

我很确定擦除N个节点至少需要O（N）时间，因为仅为每个节点分配内存是线性的。无论采用哪种智能方式，在新起点和新终点之间放置节点都是线性的。另一种等效的方法是提取节点并更改其密钥。但是，这只会将冗余密钥移到末尾而不是中间。

正确的答案可能在新添加的成员函数中的某个位置-map :: extract或map :: merge。如果std :: map的声明允许异构查找（带有专门设计的“范围键”类型的equal_range），则也可以仅通过一次调用找到开始和结束插入位置。但是，这将不利于线性O（N）擦除部分。

#define CATCH_CONFIG_MAIN
#include "catch.hpp"


#include <map>
#include <limits>

template<typename K, typename V>
class interval_map {
public:
    std::map<K, V> m_map;


    // constructor associates whole range of K with val by inserting (K_min, val)
    // into the map
    interval_map(V const& val) {
        m_map.insert(m_map.end(), std::make_pair(std::numeric_limits<K>::lowest(), val));
    }

    // Assign value val to interval [keyBegin, keyEnd).
    // Overwrite previous values in this interval.
    // Conforming to the C++ Standard Library conventions, the interval
    // includes keyBegin, but excludes keyEnd.
    // If !( keyBegin < keyEnd ), this designates an empty interval,
    // and assign must do nothing.
    void assign(K const& keyBegin, K const& keyEnd, V const& val) {
        if (!(keyBegin < keyEnd))
            return;

        typename std::map<K, V>::iterator iterBegin; /*The new begin with val, can be begin()*/
        typename std::map<K, V>::iterator iterEnd;   /*the new end of val, can be end()*/

        auto lowerKeyBegin = m_map.lower_bound(keyBegin); //either end() or some iter whose key is not less than keyBegin. [1st O(logN)]
        auto upperKeyEnd = m_map.upper_bound(keyEnd); //some iter where keyEnd < key, or end()  [2nd O(logN)]
        auto prevKeyEnd = std::prev(upperKeyEnd);

        /*
        The next interval of the new interval starts at keyEnd if the previous value at keyEnd differed from val
        */
        if (!(prevKeyEnd->second == val))
        {
            // prevKeyEnd is either less than the new end we are inserting, or the same (no update to avoid copying from erased node)
            if (!(prevKeyEnd->first < keyEnd) && !(keyEnd < prevKeyEnd->first))
                iterEnd = prevKeyEnd;
            else
                iterEnd = m_map.insert_or_assign(upperKeyEnd, keyEnd, prevKeyEnd->second);
        }
        else
        {
            iterEnd = upperKeyEnd;
        }

        /*
        The new interval starts at keyBegin if the would-be previous interval has a different value.
        Previous interval is either a key in the map less than keyBegin, or non-existent when lower_bound is m_map.begin()
        The new interval's start is merged with previous interval, if the previous interval has the same value.
        */
        if (lowerKeyBegin != m_map.begin())
        {
            auto prevIter = std::prev(lowerKeyBegin); //safe when end(), because we always have at least one value
            if (!(prevIter->second == val))
            {
                iterBegin = m_map.insert_or_assign(lowerKeyBegin, keyBegin, val);
            }
            else iterBegin = prevIter;
        }
        else
        {
            iterBegin = m_map.insert_or_assign(lowerKeyBegin, keyBegin, val);
        }

        /*
        Erase all keys between the new begin and end (excluding) so that there is only one value after iterBegin
        This is fine when iterEnd is end()
        */
        {
            auto nextIterOfBegin = std::next(iterBegin);//somehow msvc doesn't support if-initialization
            if (nextIterOfBegin != m_map.end())
            {
                //I would be very interested in a smarter way to get rid of this part without additional storage ...
                m_map.erase(nextIterOfBegin, iterEnd); 
            }
        }

        ////debug - check canonical
        //for (auto iter = m_map.begin(); iter != m_map.end(); ++iter)
        //{
        //  auto next = std::next(iter);
        //  if (next != m_map.end() && iter->second == next->second)
        //  {
        //      throw;
        //  }
        //}
    }

    // look-up of the value associated with key
    V const& operator[](K const& key) const {
        return (--m_map.upper_bound(key))->second;
    }
};

// Many solutions we receive are incorrect. Consider using a randomized test
// to discover the cases that your implementation does not handle correctly.
// We recommend to implement a test function that tests the functionality of
// the interval_map, for example using a map of unsigned int intervals to char.

struct TestKeyType
{
    unsigned int val;
    constexpr TestKeyType(unsigned int val) : val(val) {}
    constexpr bool operator<(const TestKeyType& other) const { return val < other.val; }
};

namespace std {
    template<> class numeric_limits<TestKeyType> {
    public:
        static constexpr TestKeyType lowest() { return TestKeyType(numeric_limits<unsigned int>::lowest()); }
        //static constexpr TestKeyType lowest() { return TestKeyType(-250); }
    };
}

using TestValueType = char;

struct TestFloatKeyType
{
    float val;

    TestFloatKeyType() = default;

    TestFloatKeyType(float val) : val(val) {}
    bool operator< (TestFloatKeyType other) const
    {
        return other.val - val > 1.e-4f;
    }
};

namespace std {
    template<> class numeric_limits<TestFloatKeyType> {
    public:
        static TestFloatKeyType lowest() { return TestFloatKeyType(numeric_limits<float>::lowest()); }
    };
}

TEST_CASE("EmptyRange")
{
    interval_map<TestKeyType, TestValueType> m('A');
    m.assign(3, 3, 'B');
    REQUIRE(m.m_map.count(3) == 0);

    m.assign(3, 2, 'B');
    REQUIRE(m.m_map.count(2) == 0);
    REQUIRE(m.m_map.count(3) == 0);
}


TEST_CASE("TrivialRange")
{
    interval_map<TestKeyType, TestValueType> m('A');
    m.assign(1, 10, 'B');
    REQUIRE(m[0] == 'A');
    for (int i = 1; i < 10; i++)
    {
        REQUIRE(m[i] == 'B');
    }
    REQUIRE(m[10] == 'A');
}

TEST_CASE("TrivialTwoRange")
{
    interval_map<TestKeyType, TestValueType> m('A');
    m.assign(1, 3, 'B');
    m.assign(6, 8, 'C');
    REQUIRE(m[0] == 'A');
    REQUIRE(m[1] == 'B');
    REQUIRE(m[2] == 'B');
    REQUIRE(m[3] == 'A');
    REQUIRE(m[4] == 'A');
    REQUIRE(m[5] == 'A');
    REQUIRE(m[6] == 'C');
    REQUIRE(m[7] == 'C');
    REQUIRE(m[8] == 'A');
}

TEST_CASE("OverwriteLowest")
{
    interval_map<TestKeyType, TestValueType> m('A');
    m.assign(std::numeric_limits<TestKeyType>::lowest(), 10000, 'B');
    REQUIRE(m[0] == 'B');
    REQUIRE(m[9999] == 'B');
    REQUIRE(m[10000] == 'A');
}

TEST_CASE("Merge")
{
    interval_map<TestKeyType, TestValueType> m('A');
    m.assign(std::numeric_limits<TestKeyType>::lowest(), 10, 'B');
    m.assign(10, 20, 'B');
    REQUIRE(m[0] == 'B');
    REQUIRE(m[10] == 'B');
    REQUIRE(m[19] == 'B');
    REQUIRE(m[20] == 'A');
}

TEST_CASE("FloatKey")
{
    interval_map<TestFloatKeyType, TestValueType> m('A');
    m.assign(1.f, 5.f, 'B');
    REQUIRE(m[0.f] == 'A');
    REQUIRE(m[.999999999f] == 'B');
    REQUIRE(m[1.f] == 'B');
    REQUIRE(m[4.999f] == 'B');
    REQUIRE(m[5.f] == 'A');

}

TEST_CASE("OverlappingRangeComplete")
{
    interval_map<TestKeyType, TestValueType> m('A');
    m.assign(3, 5, 'B');
    m.assign(1, 6, 'C');
    REQUIRE(m[0] == 'A');
    REQUIRE(m[1] == 'C');
    REQUIRE(m[2] == 'C');
    REQUIRE(m[3] == 'C');
    REQUIRE(m[4] == 'C');
    REQUIRE(m[5] == 'C');
    REQUIRE(m[6] == 'A');
}

TEST_CASE("OverlappingRangeInner")
{
    interval_map<TestKeyType, TestValueType> m('A');
    m.assign(1, 6, 'C');
    m.assign(3, 5, 'B');
    REQUIRE(m[0] == 'A');
    REQUIRE(m[1] == 'C');
    REQUIRE(m[2] == 'C');
    REQUIRE(m[3] == 'B');
    REQUIRE(m[4] == 'B');
    REQUIRE(m[5] == 'C');
    REQUIRE(m[6] == 'A');
}

TEST_CASE("OverlappingRangeSmallToLarge")
{
    interval_map<TestKeyType, TestValueType> m('A');
    m.assign(1, 5, 'B');
    m.assign(3, 6, 'C');
    REQUIRE(m[0] == 'A');
    REQUIRE(m[1] == 'B');
    REQUIRE(m[2] == 'B');
    REQUIRE(m[3] == 'C');
    REQUIRE(m[4] == 'C');
    REQUIRE(m[5] == 'C');
    REQUIRE(m[6] == 'A');
}

TEST_CASE("OverlappingRangeLargeToSmall")
{
    interval_map<TestKeyType, TestValueType> m('A');
    m.assign(3, 6, 'C');
    m.assign(1, 5, 'B');
    REQUIRE(m[0] == 'A');
    REQUIRE(m[1] == 'B');
    REQUIRE(m[2] == 'B');
    REQUIRE(m[3] == 'B');
    REQUIRE(m[4] == 'B');
    REQUIRE(m[5] == 'C');
    REQUIRE(m[6] == 'A');
}

TEST_CASE("ExtendingRangeBegin")
{
    interval_map<TestKeyType, TestValueType> m('A');
    m.assign(3, 5, 'B');
    m.assign(1, 4, 'B');
    REQUIRE(m[0] == 'A');
    REQUIRE(m[1] == 'B');
    REQUIRE(m[2] == 'B');
    REQUIRE(m[3] == 'B');
    REQUIRE(m[4] == 'B');
    REQUIRE(m[5] == 'A');
}

TEST_CASE("ExtendingRangeEnd")
{
    interval_map<TestKeyType, TestValueType> m('A');
    m.assign(1, 5, 'B');
    m.assign(3, 6, 'B');
    REQUIRE(m[0] == 'A');
    REQUIRE(m[1] == 'B');
    REQUIRE(m[2] == 'B');
    REQUIRE(m[3] == 'B');
    REQUIRE(m[4] == 'B');
    REQUIRE(m[5] == 'B');
    REQUIRE(m[6] == 'A');
}

TEST_CASE("ExtendingRangeBothBeginEnd")
{
    interval_map<TestKeyType, TestValueType> m('A');
    m.assign(2, 3, 'B');
    m.assign(1, 5, 'B');
    REQUIRE(m[0] == 'A');
    REQUIRE(m[1] == 'B');
    REQUIRE(m[2] == 'B');
    REQUIRE(m[3] == 'B');
    REQUIRE(m[4] == 'B');
    REQUIRE(m[5] == 'A');
}

TEST_CASE("OverwriteEndValueSafety")
{
    interval_map<TestKeyType, TestValueType> m('A');
    m.assign(2, 5, 'B');
    m.assign(5, 8, 'C');
    m.assign(4, 5, 'A');
}

TEST_CASE("ReusingExistingRangeBothBeginEnd")
{
    interval_map<TestKeyType, TestValueType> m('A');
    m.assign(1, 5, 'B');
    m.assign(2, 3, 'B');
    REQUIRE(m[0] == 'A');
    REQUIRE(m[1] == 'B');
    REQUIRE(m[2] == 'B');
    REQUIRE(m[3] == 'B');
    REQUIRE(m[4] == 'B');
    REQUIRE(m[5] == 'A');
}

TEST_CASE("ReusingEnd")
{
    interval_map<TestKeyType, TestValueType> m('A');
    m.assign(1, 5, 'B');
    m.assign(4, 6, 'A');
    REQUIRE(m[0] == 'A');
    REQUIRE(m[1] == 'B');
    REQUIRE(m[2] == 'B');
    REQUIRE(m[3] == 'B');
    REQUIRE(m[4] == 'A');
    REQUIRE(m[5] == 'A');
}

TEST_CASE("RestoringInitial")
{
    interval_map<TestKeyType, TestValueType> m('A');
    m.assign(1, 5, 'B');
    m.assign(1, 5, 'A');
    REQUIRE(m[0] == 'A');
    REQUIRE(m[1] == 'A');
    REQUIRE(m[2] == 'A');
    REQUIRE(m[3] == 'A');
    REQUIRE(m[4] == 'A');
    REQUIRE(m[5] == 'A');
}

TEST_CASE("RestoringInitial2")
{
    interval_map<TestKeyType, TestValueType> m('A');
    m.assign(1, 5, 'B');
    m.assign(0, 7, 'A');
    REQUIRE(m[0] == 'A');
    REQUIRE(m[1] == 'A');
    REQUIRE(m[2] == 'A');
    REQUIRE(m[3] == 'A');
    REQUIRE(m[4] == 'A');
    REQUIRE(m[5] == 'A');
}

TEST_CASE("VeryComplex")
{
    interval_map<TestKeyType, TestValueType> m('A');
    m.assign(3, 6, 'B');
    m.assign(2, 5, 'C');
    m.assign(4, 7, 'A');

    REQUIRE(m[1] == 'A');
    REQUIRE(m[2] == 'C');
    REQUIRE(m[3] == 'C');
    REQUIRE(m[4] == 'A');
    REQUIRE(m[5] == 'A');
    REQUIRE(m[6] == 'A');
    REQUIRE(m[7] == 'A');
}

Answer 5

void assign( K const& keyBegin, K const& keyEnd, V const& val ) {
        if (!(keyBegin < keyEnd)) return;
        else {
            // find if the val already exists
            typename std::map<K,V>::iterator i;
            for (auto i = m_map.begin(); i != m_map.end(); ++i)
                if (i->second == val)
                    return;
            m_map.insert (std::pair<K,V>(keyBegin,val));  // max efficiency inserting

            typename std::map<K,V>::iterator itr;
            std::cout << "m_map contains:\n";
            for (itr=m_map.begin(); itr!=m_map.end(); ++itr)
                std::cout << itr->first << " => " << itr->second << '\n';
            
        }
    }

我的代码到底在哪里不符合键和值类型的规范？

5 个答案: