I am currently writing a program that reads a pretty large text file and sorts the text file alphabetically and by character length. i implemented a quicksort to do this. the problem that im having and hopefully will get some clarity on is that i have two methods for quciksorting. One which is quickSortLen here is the code
void SortingCompetition::quickSortLen(vector<char*>& words, int left, int right){
int i, j, middle, underMiddle, overMiddle;
char* pivot;
//Median of FIVE pivot point
i = left;
j = right;
middle = left + (right - left) / 2;
underMiddle = left + (middle - left) / 2;
overMiddle = middle + (right - middle) / 2;
//Right and Left
if(strlen(words[right]) < strlen(words[left]))
{
swap(words[right], words[left]);
}
// 4/5 and left
if(strlen(words[overMiddle]) < strlen(words[left]))
{
swap(words[overMiddle], words[left]);
}
//Middle and Left
if(strlen(words[middle]) < strlen(words[left]))
{
swap(words[middle], words[left]);
}
// 2/5 and Middle
if(strlen(words[underMiddle]) < strlen(words[left]))
{
swap(words[underMiddle], words[left]);
}
//right and 4/5
if(strlen(words[right]) < strlen(words[underMiddle]))
{
swap(words[right], words[underMiddle]);
}
//Right and Middle
if(strlen(words[overMiddle]) < strlen(words[underMiddle]))
{
swap(words[overMiddle], words[underMiddle]);
}
//Middle and UnderMiddle
if(strlen(words[middle]) < strlen(words[underMiddle]))
{
swap(words[middle], words[underMiddle]);
}
//Right and Middle
if(strlen(words[right]) < strlen(words[middle]))
{
swap(words[right], words[middle]);
}
//OverMiddle and Middle
if(strlen(words[overMiddle]) < strlen(words[middle]))
{
swap(words[overMiddle], words[middle]);
}
//Right and OverMiddle
if(strlen(words[right]) < strlen(words[overMiddle]))
{
swap(words[right], words[overMiddle]);
}
//PIVOT POINT ESTABLISHED
pivot = words[middle];
//Partition
while (i <= j)
{
//Check from start
while (strlen(words[i]) < strlen(pivot))
{
++i;
}
//Check from end
while (strlen(words[j]) > strlen(pivot))
{
--j;
}
//Switch
if(i <= j)
{
swap(words[i], words[j]);
++i;
--j;
}
}
//Recursion
if (left < j)
{
quickSortLen(words, left, j);
}
if(i < right)
{
quickSortLen(words, i, right);
}
}
and than i have quickSortAlph here is the code for that
void SortingCompetition::quickSortAlph(vector<char*>& words, int left, int right){
int i, j, middle, underMiddle, overMiddle;
char* pivot;
int x = 1;
//Median of FIVE pivot point
i = left;
j = right;
middle = left + (right - left) / 2;
underMiddle = left + (middle - left) / 2;
overMiddle = middle + (right - middle) / 2;
//Right and Left
if(strcmp(words[right], words[left]) < 0)
{
swap(words[right], words[left]);
}
// 4/5 and left
if(strcmp(words[overMiddle], words[left]) < 0)
{
swap(words[overMiddle], words[left]);
}
//Middle and Left
if(strcmp(words[middle], words[left]) < 0)
{
swap(words[middle], words[left]);
}
// 2/5 and Middle
if(strcmp(words[underMiddle], words[left]) < 0)
{
swap(words[underMiddle], words[left]);
}
//right and 4/5
if(strcmp(words[right], words[underMiddle]) < 0)
{
swap(words[right], words[underMiddle]);
}
//Right and Middle
if(strcmp(words[overMiddle], words[underMiddle]) < 0)
{
swap(words[overMiddle], words[underMiddle]);
}
//Middle and UnderMiddle
if(strcmp(words[middle], words[underMiddle]) < 0)
{
swap(words[middle], words[underMiddle]);
}
//Right and Middle
if(strcmp(words[right], words[middle]) < 0)
{
swap(words[right], words[middle]);
}
//OverMiddle and Middle
if(strcmp(words[overMiddle], words[middle]) < 0)
{
swap(words[overMiddle], words[middle]);
}
//Right and OverMiddle
if(strcmp(words[right], words[overMiddle]) < 0)
{
swap(words[right], words[overMiddle]);
}
//PIVOT POINT ESTABLISHED
pivot = words[middle];
//Partition
while (i <= j)
{
//if((strcmp(words[i], pivot) < 0) && (strcmp(words[j], pivot) < 0)
//Check from start
while (strcmp(words[i], pivot) < 0)
{
++i;
}
//Check from end
while (strcmp(words[j], pivot) > 0)
{
--j;
}
//Switch
if((i <= j))
{
swap(words[i], words[j]);
++i;
--j;
}else{
i++;
j--;
}
}
//Recursion
if (left < j)
{
quickSortAlph(words, left, j);
}
if(i < right)
{
quickSortAlph(words, i, right);
}
}
both work as they should but im having trouble combining the two because a word like august is going to have a less ascii value than bravo but the length is of bravo is less than august. any suggestions on how to go about combining the two?
Do you really need to write your own quick sort? If you don't the you could use std::sort
with a custom compare functor.
struct string_cmp
{
bool operator()(const std::string& lhs, const std::string& rhs)
{
if (lhs.size() == rhs.size())
return lhs < rhs;
else
return lhs.size() < rhs.size();
}
};
// and then we call sort on the container
std::sort(container_name.begin(), container_name.end(), string_cmp());
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