### 如何按其他std :: vector的值对std :: vector进行排序？

31165 观看

13回复

41757 作者的声誉

``````std::vector<int> Index = { 3, 1, 2 };
std::vector<std::string> Values = { "Third", "First", "Second" };

Transformation = sort(Index);
Index is now { 1, 2, 3};

... magic happens as Transformation is applied to Values ...
Values are now { "First", "Second", "Third" };
``````

### 回应 13

4

5483 作者的声誉

31

420924 作者的声誉

friol的方法与您的方法结合在一起时很好。首先，构建一个由数字1… n组成的向量以及该向量中指示排序顺序的元素：

``````typedef vector<int>::const_iterator myiter;

vector<pair<size_t, myiter> > order(Index.size());

size_t n = 0;
for (myiter it = Index.begin(); it != Index.end(); ++it, ++n)
order[n] = make_pair(n, it);
``````

``````struct ordering {
bool operator ()(pair<size_t, myiter> const& a, pair<size_t, myiter> const& b) {
return *(a.second) < *(b.second);
}
};

sort(order.begin(), order.end(), ordering());
``````

``````template <typename T>
vector<T> sort_from_ref(
vector<T> const& in,
vector<pair<size_t, myiter> > const& reference
) {
vector<T> ret(in.size());

size_t const size = in.size();
for (size_t i = 0; i < size; ++i)
ret[i] = in[reference[i].first];

return ret;
}
``````

3

32701 作者的声誉

``````using namespace std;

template< typename Iterator, typename Comparator >
struct Index {
vector<Iterator> v;

Index( Iterator from, Iterator end, Comparator& c ){
v.reserve( std::distance(from,end) );
for( ; from != end; ++from ){
v.push_back(from); // no deref!
}
sort( v.begin(), v.end(), c );
}

};

template< typename Iterator, typename Comparator >
Index<Iterator,Comparator> index ( Iterator from, Iterator end, Comparator& c ){
return Index<Iterator,Comparator>(from,end,c);
}

struct mytype {
string name;
double number;
};

template< typename Iter >
struct NameLess : public binary_function<Iter, Iter, bool> {
bool operator()( const Iter& t1, const Iter& t2 ) const { return t1->name < t2->name; }
};

template< typename Iter >
struct NumLess : public binary_function<Iter, Iter, bool> {
bool operator()( const Iter& t1, const Iter& t2 ) const { return t1->number < t2->number; }
};

void indices() {

mytype v[] =    { { "me"    ,  0.0 }
, { "you"   ,  1.0 }
, { "them"  , -1.0 }
};
mytype* vend = v + _countof(v);

Index<mytype*, NameLess<mytype*> > byname( v, vend, NameLess<mytype*>() );
Index<mytype*, NumLess <mytype*> > bynum ( v, vend, NumLess <mytype*>() );

assert( byname.v[0] == v+0 );
assert( byname.v[1] == v+2 );
assert( byname.v[2] == v+1 );

assert( bynum.v[0] == v+2 );
assert( bynum.v[1] == v+0 );
assert( bynum.v[2] == v+1 );

}
``````

8

10587 作者的声誉

9

453 作者的声誉

``````typedef std::vector<int> int_vec_t;
typedef std::vector<std::string> str_vec_t;
typedef std::vector<size_t> index_vec_t;

class SequenceGen {
public:
SequenceGen (int start = 0) : current(start) { }
int operator() () { return current++; }
private:
int current;
};

class Comp{
int_vec_t& _v;
public:
Comp(int_vec_t& v) : _v(v) {}
bool operator()(size_t i, size_t j){
return _v[i] < _v[j];
}
};

index_vec_t indices(3);
std::generate(indices.begin(), indices.end(), SequenceGen(0));
//indices are {0, 1, 2}

int_vec_t Index = { 3, 1, 2 };
str_vec_t Values = { "Third", "First", "Second" };

std::sort(indices.begin(), indices.end(), Comp(Index));
//now indices are {1,2,0}
``````

3

14190 作者的声誉

1

31 作者的声誉

ltjax的答案是一种很好的方法-实际上是在boost的zip_iterator中实现的http://www.boost.org/doc/libs/1_43_0/libs/iterator/doc/zip_iterator.html

1

2565 作者的声誉

``````#include <boost/iterator/counting_iterator.hpp>
#include <vector>
#include <algorithm>

std::vector<double> keys = ...
std::vector<double> values = ...

std::vector<size_t> indices(boost::counting_iterator<size_t>(0u), boost::counting_iterator<size_t>(keys.size()));
std::sort(begin(indices), end(indices), [&](size_t lhs, size_t rhs) {
return keys[lhs] < keys[rhs];
});

// Now to iterate through the values array.
for (size_t i: indices)
{
std::cout << values[i] << std::endl;
}
``````

1

16 作者的声誉

``````template<typename T>
struct applyOrderinPlace
{
void operator()(const vector<size_t>& order, vector<T>& vectoOrder)
{
vector<bool> indicator(order.size(),0);
size_t start = 0, cur = 0, next = order[cur];
size_t indx = 0;
T tmp;

while(indx < order.size())
{
//find unprocessed index
if(indicator[indx])
{
++indx;
continue;
}

start = indx;
cur = start;
next = order[cur];
tmp = vectoOrder[start];

while(next != start)
{
vectoOrder[cur] = vectoOrder[next];
indicator[cur] = true;
cur = next;
next = order[next];
}
vectoOrder[cur] = tmp;
indicator[cur] = true;
}
}
};
``````

0

5185 作者的声誉

``````void ordered_pairs()
{
std::vector<std::string> names;
std::vector<int> ages;

// read input and populate the vectors
populate(names, ages);

// print input
print(names, ages);

// sort pairs
std::vector<std::string> sortedNames(names);
std::sort(sortedNames.begin(), sortedNames.end());

std::vector<int> indexMap;
for(unsigned int i = 0; i < sortedNames.size(); ++i)
{
for (unsigned int j = 0; j < names.size(); ++j)
{
if (sortedNames[i] == names[j])
{
indexMap.push_back(j);
break;
}
}
}
// use the index mapping to match the ages to the names
std::vector<int> sortedAges;
for(size_t i = 0; i < indexMap.size(); ++i)
{
sortedAges.push_back(ages[indexMap[i]]);
}

std::cout << "Ordered pairs:\n";
print(sortedNames, sortedAges);
}
``````

``````void populate(std::vector<std::string>& n, std::vector<int>& a)
{
std::string prompt("Type name and age, separated by white space; 'q' to exit.\n>>");
std::string sentinel = "q";

while (true)
{
std::cout << prompt;
std::string input;
getline(std::cin, input);

// exit input loop
if (input == sentinel)
{
break;
}

std::stringstream ss(input);

// extract input
std::string name;
int age;
if (ss >> name >> age)
{
n.push_back(name);
a.push_back(age);
}
else
{
std::cout <<"Wrong input format!\n";
}
}
}
``````

``````void print(const std::vector<std::string>& n, const std::vector<int>& a)
{
if (n.size() != a.size())
{
std::cerr <<"Different number of names and ages!\n";
return;
}

for (unsigned int i = 0; i < n.size(); ++i)
{
std::cout <<'(' << n[i] << ", " << a[i] << ')' << "\n";
}
}
``````

``````#include <iostream>
#include <sstream>
#include <string>
#include <vector>
#include <algorithm>

void ordered_pairs();
void populate(std::vector<std::string>&, std::vector<int>&);
void print(const std::vector<std::string>&, const std::vector<int>&);

//=======================================================================
int main()
{
std::cout << "\t\tSimple name - age sorting.\n";
ordered_pairs();
}
//=======================================================================
// Function Definitions...
``````

0

56 作者的声誉

``````**// C++ program to demonstrate sorting in vector
// of pair according to 2nd element of pair
#include <iostream>
#include<string>
#include<vector>
#include <algorithm>

using namespace std;

// Driver function to sort the vector elements
// by second element of pairs
bool sortbysec(const pair<char,char> &a,
const pair<int,int> &b)
{
return (a.second < b.second);
}

int main()
{
// declaring vector of pairs
vector< pair <char, int> > vect;

// Initialising 1st and 2nd element of pairs
// with array values
//int arr[] = {10, 20, 5, 40 };
//int arr1[] = {30, 60, 20, 50};
char arr[] = { ' a', 'b', 'c' };
int arr1[] = { 4, 7, 1 };

int n = sizeof(arr)/sizeof(arr[0]);

// Entering values in vector of pairs
for (int i=0; i<n; i++)
vect.push_back( make_pair(arr[i],arr1[i]) );

// Printing the original vector(before sort())
cout << "The vector before sort operation is:\n" ;
for (int i=0; i<n; i++)
{
// "first" and "second" are used to access
// 1st and 2nd element of pair respectively
cout << vect[i].first << " "
<< vect[i].second << endl;

}

// Using sort() function to sort by 2nd element
// of pair
sort(vect.begin(), vect.end(), sortbysec);

// Printing the sorted vector(after using sort())
cout << "The vector after sort operation is:\n" ;
for (int i=0; i<n; i++)
{
// "first" and "second" are used to access
// 1st and 2nd element of pair respectively
cout << vect[i].first << " "
<< vect[i].second << endl;
}
getchar();
return 0;`enter code here`
}**
``````

-2

72 作者的声誉

C ++，基于另一个对一个向量进行排序

0

72 作者的声誉

``````template< typename T, typename U >
std::vector<T> sortVecAByVecB( std::vector<T> & a, std::vector<U> & b ){

// zip the two vectors (A,B)
std::vector<std::pair<T,U>> zipped(a.size());
for( size_t i = 0; i < a.size(); i++ ) zipped[i] = std::make_pair( a[i], b[i] );

// sort according to B
std::sort(zipped.begin(), zipped.end(), []( auto & lop, auto & rop ) { return lop.second < rop.second; });

// extract sorted A
std::vector<T> sorted;
std::transform(zipped.begin(), zipped.end(), std::back_inserter(sorted), []( auto & pair ){ return pair.first; });

return sorted;
}
``````