single.cpp

/*
 * Single Threaded Starter Code
 * 
 * The following definition of the sort member function is the reference solution
 * for the correct sort output. Your multithreaded implementation should produce
 * the same output as this function, and should be much faster.
 */

#include "BucketSort.h"

#include <algorithm>
#include <cmath>

bool aLessB(const unsigned int& x, const unsigned int& y, unsigned int pow) {
    if (x == y) return false; // if the two numbers are the same then one is not less than the other
    
    unsigned int a = x;
    unsigned int b = y;
    
    // work out the digit we are currently comparing on. 
        if (pow == 0) {
            while (a / 10 > 0) {
                a = a / 10; 
            }   
            while (b / 10 > 0) {
                b = b / 10;
            }
        } else {
            while (a / 10 >= (unsigned int) std::round(std::pow(10,pow))) {
                a = a / 10;
            }
            while (b / 10 >= (unsigned int) std::round(std::pow(10,pow))) {
                b = b / 10;
            }
        }

    if (a == b)
        return aLessB(x,y,pow + 1);  // recurse if this digit is the same 
    else
        return a < b;
}

// TODO: replace this with a parallel version. 
void BucketSort::sort(unsigned int numCores) {
    std::sort(numbersToSort.begin(),numbersToSort.end(), [](const unsigned int& x, const unsigned int& y){
        return aLessB(x,y,0);
    });
}