I need help writing this function. I'm not too familiar with vectors

LANGUAGE: C++

//REQUIRES: v is not empty

//EFFECTS: returns a summary of the dataset as (value, frequency) pairs

// In the returned vector-of-vectors, the inner vector is a (value, frequency)

// pair. The outer vector contains many of these pairs. The pairs should be

// sorted by value.

// {

// {1, 2},

// {2, 3},

// {17, 1}

// }

// This means that the value 1 occurred twice, the value 2 occurred 3 times,

// and the value 17 occurred once

std::vector > summarize(std::vector v);

We are also given a sorting function that sorts the vector from smallest to largest number.

//MODIFIES: v

//EFFECTS: sorts v

void sort(std::vector &v);