Question

#include <iostream>
#include <cstdio>
#include <set>
#include <vector>

using namespace std;

int main() {
    vector<int> S, P, R;
    set<vector<int> > SS;
    S.push_back(9);
    S.push_back(9);
    S.push_back(9);
    P.push_back(656);
    P.push_back(11);
    P.push_back(10);
    R.push_back(10);
    R.push_back(11);
    R.push_back(656);
    SS.insert(R);
    SS.insert(S);
    SS.insert(P);
    set<vector<int> >::iterator itr;
    vector<int>::iterator i;
    for(itr = SS.begin(); itr != SS.end(); itr++) {
        for(i = itr -> begin(); i != itr -> end(); i++) {
            cout<<*i<<" ";
        }
    }
    return 0;
}

应显示向量S和P的值或向量R和S.不能使用set<set<int> >，因为它会拆除向量S的值。

Answer 1

#include <iostream>
#include <vector>
#include <algorithm>
#include <functional>

using initial_vector = std::vector<int>;
using vector_of_vecs = std::vector<initial_vector>;

template<class...Args>
vector_of_vecs uniqify(Args&&...args)
{
    // build a temporary vector of vectors
    vector_of_vecs result { args... };

    // sort it. std::unique requires the vector to be sorted
    sort(result.begin(), result.end());

    // erase all items that are not unique.
    result.erase(std::unique(result.begin(),
                             result.end()),
                 result.end());

    // return the result
    return result;
}


auto main() -> int
{
    using namespace std;

    vector<int> A, B, C;
    A = {2, 4, 5};
    B = {2, 2, 2};
    C = {2, 4, 5};

    // note: to avoid copies, simply move the vectors into uniquify
    auto uv = uniqify(std::move(A), std::move(B), std::move(C));

    // or preserve the source vectors and force copies if you wish
    //auto uv = uniqify(A, B, C);

    // uv is now a vector of unique vectors.

    // print out our vector of unique vectors
    for(const auto& i : uv){
        cout << '[';
        auto sep = " ";
        for (const auto& j : i) {
            cout << sep << j;
            sep = ", ";
        }
        cout << " ]\n";
    }

    return 0;
}

预期结果：

[ 2, 2, 2 ]
[ 2, 4, 5 ]

Answer 2

使用一组多重集。 multiset就像一个向量，但是已经排序，因此P和R（转换为多集）将是相等的。

set<multiset<int> > SS;
....
SS.insert(multiset(R.begin(), R.end());
SS.insert(multiset(S.begin(), S.end());
SS.insert(multiset(P.begin(), P.end());

如何从c ++中的一组向量中删除重复的向量？

2 个答案: