Introduction to Algorithms: Quick sort and insert sort

Code implementation

1 #ifndef _sort_h2 #define_sort_h3 4 //Goal:quicksort and Insertsort5 //time:12/2/20146 //Author:zrss7 //reference:introduction to Algorithms8 9 classSort {Ten  Public: One     voidQuickSort (intA[],intPintR); A     voidInsertsort (intA[],intPintR); -  - Private: the     intPartitionintA[],intPintR);//For QuickSort - }; -  - intSort::p artition (intA[],intPintr) { +     intx = A[r];//Use A[r] as pivot node -      +     inti = P-1;// point to left part A  at     //divide A Array to three part -     //A[p-i] <= x -     //a[(i + 1)-J] > x -     //a[(j + 1)-R) Unknown -      for(intj = P; J < R; ++j) { -         if(A[j] <=x) { in++i; -             if(I! = j) {//swap a[i] and A[j] to                 inttemp =A[i]; +A[i] =A[j]; -A[J] =temp; the             } *         } $     }Panax Notoginseng  -     //Exchange A[i + 1] and A[r] theA[r] = a[i +1]; +A[i +1] =x; A  the     return(i +1); + } -  $ voidSort::quicksort (intA[],intPintr) { $     if(P <r) { -         intQ =partition (A, p, R); -QuickSort (A, p, Q-1); theQuickSort (A, q +1, R); -     }Wuyi } the  - voidSort::insertsort (intA[],intPintr) { Wu      for(intj = p +1; J <= R; ++j) { -         intKey =A[j]; About         inti = J-1; $          while(I >= p && a[i] > key) {//Move Backward -A[i +1] =A[i]; ---i; -         } A  +         if(i +1! = j) {//Insert A[j] to right position theA[i +1] =key; -         } $     } the } the  the  the #endif

Insert sort vs. Quick Sort Run time comparison

Randomly generate 100,000 int test data

1#include <cstdio>2#include <cstdlib>3#include"windows.h"4#include"sort.h"5 6 intMainvoid) {7     Const intLength =100000;8     intNumber[length];9 Ten      for(inti =0; i < length; ++i) { OneNumber[i] =rand (); A     } -  - sort sort; the  -DWORD st =GetTickCount (); -  -Sort.insertsort (number,0, Length-1); +     //sort.quicksort (number, 0, length-1); -  +DWORD ed =GetTickCount (); A  atprintf"Insertsort Use time:%dms\n", Ed-St); -     //printf ("QuickSort Use time:%dms\n", ed-st); -  -System"Pause"); -     return 0; -}

Insertsort Use time:2200ms

QuickSort Use time:0ms

System Information

System:windows 7 Professional Service Pack 1

Cpu:intel (R) Pentium (r) Dual CPU E2220 @ 2.40GHz 2.40GHz

memory:3.00 GB

Conclusion

The efficiency of fast sorting is better than the insertion sort when the input is 100, 000 orders of magnitude, and the input data is a random value

Introduction to Algorithms: Quick sort and insert sort