send array from qml to c++

Send array from c++ to qml like below, it's OK

std::vector<std::vector<int> > getDataFromCPP2QML();

but, if send array from qml to c++ like this:

void setDataFromQML2CPP(const std::vector<std::vector<int> > array);

Array in qml is: [ [1, 2, 3],  [4, 5] ]

but in CPP, it will be: [ [1, 2, 3], [1, 2, 3, 4, 5] ], data duplication