Initializing std::vector with unique_ptr

I can do this:

#include <vector>
#include <memory>
int main(int argc, char const *argv[]) {
    int size = 5;
    int *array = new int[size];
    std::vector<int> v(array, array+size);
    delete[] array;
}

And, with smart porter, this (alt1):

#include <vector>
#include <memory>
int main(int argc, char const *argv[]) {
    std::unique_ptr<int[]> array(new int[size]);
    std::vector<int> v(array.get(), array.get()+size);
}

And I was wondering, with all this smartness in place, if something even shorter (alt2) would be ok:

#include <vector>
#include <memory>
int main(int argc, char const *argv[]) {
    std::unique_ptr<int[]> array(new int[size]);
    std::vector<int> v(array);
}

But compiler says no:

c++ -std=gnu++14 -g -Wall -O3  -c -o main.o main.cpp
main.cpp:6:19: error: no matching constructor for initialization of 'std::vector<int>'
        std::vector<int> v(array);

So, alt1 is the shortest way to init std::vector with unique_ptr?