QuickSelect Algorithm Understanding

Question

I\'ve been poring over various tutorials and articles that discuss quicksort and quickselect, however my understanding of them is still shaky.

Given this code struct

Answer 1

btw, your code has a few bugs..

int quickSelect(int items[], int first, int last, int k) {
    int pivot = partition(items, first, last);
    if (k < pivot-first+1) { //boundary was wrong
        return quickSelect(items, first, pivot, k);
    } else if (k > pivot-first+1) {//boundary was wrong
        return quickSelect(items, pivot+1, last, k-pivot);
    } else {
        return items[pivot];//index was wrong
    }
}