1. 1 Partitioning in Quicksort How do we partition in-place efficiently? n Partition element = rightmost element. n Scan from left for larger element. n Scan from right for smaller element. n Exchange. n Repeat until pointers cross. QUICKSORTISCOOL partitioned partition elementleft right unpartitioned

2. 2 Partitioning in Quicksort swap me partitioned partition elementleft right unpartitioned QUICKSORTISCOOL How do we partition in-place efficiently? n Partition element = rightmost element. n Scan from left for larger element. n Scan from right for smaller element. n Exchange. n Repeat until pointers cross.

3. 3 Partitioning in Quicksort partitioned partition elementleft right unpartitioned swap me QUICKSORTISCOOL How do we partition in-place efficiently? n Partition element = rightmost element. n Scan from left for larger element. n Scan from right for smaller element. n Exchange. n Repeat until pointers cross.

4. 4 Partitioning in Quicksort partitioned partition elementleft right unpartitioned swap me QUICKSORTISCOOL How do we partition in-place efficiently? n Partition element = rightmost element. n Scan from left for larger element. n Scan from right for smaller element. n Exchange. n Repeat until pointers cross.

5. 5 Partitioning in Quicksort partitioned partition elementleft right unpartitioned swap me QUICKSORTISCOOL How do we partition in-place efficiently? n Partition element = rightmost element. n Scan from left for larger element. n Scan from right for smaller element. n Exchange. n Repeat until pointers cross.

6. 6 Partitioning in Quicksort partitioned partition elementleft right unpartitioned CUICKSORTISQOOL How do we partition in-place efficiently? n Partition element = rightmost element. n Scan from left for larger element. n Scan from right for smaller element. n Exchange. n Repeat until pointers cross.

7. 7 Partitioning in Quicksort swap me partitioned partition elementleft right unpartitioned CUICKSORTISQOOL How do we partition in-place efficiently? n Partition element = rightmost element. n Scan from left for larger element. n Scan from right for smaller element. n Exchange. n Repeat until pointers cross.

8. 8 Partitioning in Quicksort partitioned partition elementleft right unpartitioned swap me CUICKSORTISQOOL How do we partition in-place efficiently? n Partition element = rightmost element. n Scan from left for larger element. n Scan from right for smaller element. n Exchange. n Repeat until pointers cross.

9. 9 Partitioning in Quicksort partitioned partition elementleft right unpartitioned swap me CUICKSORTISQOOL How do we partition in-place efficiently? n Partition element = rightmost element. n Scan from left for larger element. n Scan from right for smaller element. n Exchange. n Repeat until pointers cross.

10. 10 Partitioning in Quicksort partitioned partition elementleft right unpartitioned CIICKSORTUSQOOL How do we partition in-place efficiently? n Partition element = rightmost element. n Scan from left for larger element. n Scan from right for smaller element. n Exchange. n Repeat until pointers cross.

11. 11 Partitioning in Quicksort partitioned partition elementleft right unpartitioned CIICKSORTUSQOOL How do we partition in-place efficiently? n Partition element = rightmost element. n Scan from left for larger element. n Scan from right for smaller element. n Exchange. n Repeat until pointers cross.

12. 12 Partitioning in Quicksort partitioned partition elementleft right unpartitioned CIICKSORTUSQOOL How do we partition in-place efficiently? n Partition element = rightmost element. n Scan from left for larger element. n Scan from right for smaller element. n Exchange. n Repeat until pointers cross.

13. 13 Partitioning in Quicksort partitioned partition elementleft right unpartitioned CIICKSORTUSQOOL How do we partition in-place efficiently? n Partition element = rightmost element. n Scan from left for larger element. n Scan from right for smaller element. n Exchange. n Repeat until pointers cross.

14. 14 Partitioning in Quicksort swap me partitioned partition elementleft right unpartitioned CIICKSORTUSQOOL How do we partition in-place efficiently? n Partition element = rightmost element. n Scan from left for larger element. n Scan from right for smaller element. n Exchange. n Repeat until pointers cross.

15. 15 Partitioning in Quicksort partitioned partition elementleft right unpartitioned swap me CIICKSORTUSQOOL How do we partition in-place efficiently? n Partition element = rightmost element. n Scan from left for larger element. n Scan from right for smaller element. n Exchange. n Repeat until pointers cross.

16. 16 Partitioning in Quicksort partitioned partition elementleft right unpartitioned swap me CIICKSORTUSQOOL How do we partition in-place efficiently? n Partition element = rightmost element. n Scan from left for larger element. n Scan from right for smaller element. n Exchange. n Repeat until pointers cross.

17. 17 Partitioning in Quicksort partitioned partition elementleft right unpartitioned swap me CIICKSORTUSQOOL How do we partition in-place efficiently? n Partition element = rightmost element. n Scan from left for larger element. n Scan from right for smaller element. n Exchange. n Repeat until pointers cross.

18. 18 Partitioning in Quicksort pointers cross swap with partitioning element partitioned partition elementleft right unpartitioned CIICKSORTUSQOOL How do we partition in-place efficiently? n Partition element = rightmost element. n Scan from left for larger element. n Scan from right for smaller element. n Exchange. n Repeat until pointers cross.

19. 19 Partitioning in Quicksort partitioned partition elementleft right unpartitioned partition is complete CIICKLORTUSQOOS How do we partition in-place efficiently? n Partition element = rightmost element. n Scan from left for larger element. n Scan from right for smaller element. n Exchange. n Repeat until pointers cross.