Step-by-Step Guide to the Interior Design Process for an Illustrated Novel
Quicksort: illustrated step-by-step walk through
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Quicksort algorithm Illustrated walkthrough
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A step-by-step illustration of Quicksort to help you walk through a series of operations. Illustration is accompanied by actual code with bold line indicating the current operation.
Transcript of Quicksort: illustrated step-by-step walk through
Quicksort algorithmIllustrated walkthrough
Partition function
This function does the most of the heavy lifting, so we look at it first, then see it in the context of Quicksort algorithm
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[0]
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
[1] [2] [3] [4] [5]
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
istore Index
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begin last
0
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
store Index
i
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
0store Index
0i
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
0store Index
0i
0 < 5is true
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
0store Index
0i
12 <= 11is false
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
0store Index
1i
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
0store Index
1i
7 <= 11is true
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
0store Index
1i
Swap
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
0store Index
1i
Swap
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
1store Index
1i
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
1store Index
2i
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
1store Index
2i
2 < 5is true
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
1store Index
2i
14 <= 11is fase
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
1store Index
3i
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
1store Index
3i3 < 5is true
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
1store Index
3i9 <= 11is true
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
1store Index
3i
Swap
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
1store Index
3i
Swap
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
2store Index
3i
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
2store Index
4i
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
2store Index
4i4 < 5is true
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
2store Index
4i10 <= 11
is true
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
2store Index
4i
Swap
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
2store Index
4i
Swap
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
3store Index
4i
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
3store Index
5i
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
3store Index
5i
4 < 5is false
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
3store Index
5i
Swap
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
3store Index
5i
Swap
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begin last
int storeIndex = begin;for (int i = begin; i < last; i++) { if (array[i] <= array[last]) { Swap(array, i, storeIndex); storeIndex = storeIndex + 1; }}Swap(array, storeIndex, last);return storeIndex;
3store Index
5i
Quicksort algorithm
Now we use Partition in the context of Quicksort
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int pivotIndex = 0;if (begin < last) { pivotIndex = Partition(array, begin, last); QuickSort(array, begin, pivotIndex - 1); QuickSort(array, pivotIndex + 1, last); }else { return;}
pivot Index
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
0pivot Index
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
0pivot Index
0 < 9is true
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
0pivot Index
Partition0..9
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
3pivot Index
these are <= 6 these are > 6
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
3pivot Index
Call Stack #0
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
pivot Index
Call Stack #0
Call Stack #1
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
0pivot Index
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
0pivot Index
0 < 2is true
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
0pivot Index
Partition0..2
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
1pivot Index
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
1pivot Index
Call Stack #0
Call Stack #1
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
Call Stack #0
Call Stack #1
pivot Index
Call Stack #2
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
Call Stack #0
Call Stack #1
0pivot Index
Call Stack #2
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
Call Stack #0
Call Stack #1
0pivot Index
Call Stack #20 < 0
is false
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
Call Stack #0
Call Stack #1
0pivot Index
Call Stack #2
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
1pivot Index
Call Stack #0
Call Stack #1
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
Call Stack #0
Call Stack #1
pivot Index
Call Stack #2
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
Call Stack #0
Call Stack #1
0pivot Index
Call Stack #2
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
Call Stack #0
Call Stack #1
0pivot Index
Call Stack #20 < 0is false
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
Call Stack #0
Call Stack #1
0pivot Index
Call Stack #2
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
1pivot Index
Call Stack #0
Call Stack #1
return (at the end of the function. Implicit ‘return’ statement
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
3pivot Index
Call Stack #0
We are done with these elements!
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int pivotIndex = 0;if (start < end) { pivotIndex = Partition(array, start, end); QuickSort(array, start, pivotIndex - 1); QuickSort(array, pivotIndex + 1, end); }else { return;}
pivot Index
Call Stack #0
Call Stack #1
Walkthrough ends here.The right hand side is also sorted as it recursively calls Quicksort.
