归并排序

一、用数组临时存储

#include <iostream>using namespace std;const int N = 5;int a[N];void MergeSort(int left,int right);void Merge(int left,int mid,int right);void main(){int i;cout<<"Input "<< N <<" numbers please:";for(i=0;i<N;i++)cin >> a[i];MergeSort(0,N-1);cout << "The sorted array is" << endl;for(i=0;i<N;i++)cout << a[i] << " ";cin.get(); cin.get();}void MergeSort(int left,int right){int mid = 0;if(left < right){mid = (left + right) / 2;MergeSort(left,mid);MergeSort(mid+1,right);Merge(left,mid,right);}}void Merge(int left,int mid,int right){int i = left, j = mid + 1, k = left;int temp[N]; while( (i <= mid) && (j <= right) ){if( a[i] <= a[j] )temp[k++] = a[i++];else temp[k++] = a[j++];}for(int q=i; q <= (i>mid?right:mid); q++)temp[k++] = a[q];for(i=left;i<=right;i++)a[i] = temp[i];}

 

二、用数组模拟链表

#include <iostream>#include <ctime>#include <windows.h>using namespace std;const int N = 1000;int a[N+1],link[N+1];void CreatRandomArray(int a[],int b[]);void PrintArray(int a[]);void PrintMerge(int i);int MergeSort(int left,int right);int Merge(int p,int q);void main(){int head;double t,ave[10];LARGE_INTEGER begin,end,clocks;QueryPerformanceFrequency(&clocks); //每秒多少个clockfor (int i=0;i<10;i++){CreatRandomArray(a,link);//PrintArray(a);QueryPerformanceCounter(&begin); //计时开始head = MergeSort(1,N);QueryPerformanceCounter(&end); //计时结束//PrintMerge(head);t = (end.QuadPart-begin.QuadPart+0.0)/clocks.QuadPart;ave[i] = t;//cout << endl << "Totle time:"<< t << "sec" << endl;}t = 0;for (int i=0;i<10;i++)t += ave[i];t /= 10;cout << endl << "The average time:"<< t << "sec" << endl;}int MergeSort(int left,int right){int mid,p,q;if(left < right){mid = (left + right) / 2;p = MergeSort(left,mid);q = MergeSort(mid+1,right);return Merge(p,q);}elsereturn left;}int Merge(int p,int q){int k = 0; while( (p != 0) && (q != 0) ){if( a[p] <= a[q] ){link[k] = p;k = p;p = link[p];}else{link[k] = q;k = q;q = link[q];}}if ( p == 0 )link[k] = q;elselink[k] = p;return link[0];}void CreatRandomArray(int a[],int link[]){LARGE_INTEGER seed;QueryPerformanceCounter(&seed);srand(seed.QuadPart);for (int i=0;i<=N;i++){a[i] = rand() % 10000;link[i] = 0;}}void PrintArray(int a[]){cout << "The Random array is" << endl;for (int i=1;i<=N;i++)cout << a[i] <<" ";cout << endl << endl;}void PrintMerge(int i){cout << "The MergeSorted array is" << endl;cout << a[i] << " ";while (link[i] != 0){i = link[i];cout << a[i] << " ";}}