#include <vector>
#include <algorithm>
#include <iostream>
 
int main()
{
    using namespace std;
 
    vector<int> v = { 1, 4, 7, 8, 11 };
    vector<vector<int>> result;
 
    for (auto i = v.begin(), e = v.end(); i != e; ) {
        auto f = adjacent_find(i, e, [](auto l, auto r) -> bool { return (r - l) >= 2; });
        if (f != e) ++f;
        result.emplace_back(i, f);
        i = f;
    }
 
    for (auto && i : result ) {
        for (auto && j : i)
            cout << j << " , ";
        cout << "\n";
    }
}
 

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