Partial sorting

Questions 1 to 5 of 6

1. 1. What does this code print? ``cpp vector<int> v = {9, 4, 7, 1, 8}; partial_sort(v.begin(), v.begin() + 2, v.end()); cout << v[0] << ' ' << v[1] << '\n'; ``

   4 11 79 41 4
2. 2. What does best hold after this code runs? ``cpp vector<int> src = {3, 9, 1, 7}; vector<int> best(3); partial_sort_copy(src.begin(), src.end(), best.begin(), best.end()); ``

   9 7 31 3 91 3 73 1 7
3. 3. After nth_element(v.begin(), v.begin() + 2, v.end()) runs on 5 2 8 1 9, which statement is guaranteed to be true?

   The whole vector is sorted in ascending orderv[0] and v[1] hold the two smallest values, in ascending orderv[2] holds the value a full sort would put there, with nothing on its left bigger and nothing on its right smallerThe values on each side of index 2 are sorted, so v[0] is the smallest
4. 4. Roughly how many comparisons does std::nth_element need, on average, to place one chosen value in its correct position in a list of n values?

   About n log n, the same as a full sortAbout nAbout n log k, where k is the rank asked forAbout log n
5. 5. A program needs the top 5 scores in descending order, and the original vector must stay unchanged. Which call fits?

   partial_sort_copy into a result vector of size 5, with greater<int>()partial_sort on the original vector, with the first five positionsnth_element on a copy, then print the first five valuesstd::stable_sort on the original vector