1）④排序算法之归并排序

  1 #include "iostream"
  2 #include "vector"
  3 #include "time.h"
  4 #include "iomanip"
  5 using namespace std;
  6
  7 #define num 25
  8 typedef int type;//type类型为int
  9
 10 /*
 11 *将非降数组A,B,中的元素
 12 */
 13 void merge(vector<type>A,vector<type>B,vector<type>&C,int flags)
 14 {
 15     int ia =0,ib=0,ic=0;
 16     if(flags==1)//升序
 17     {
 18         while(ia<A.size()&&ib<B.size())
 19         {
 20             if(A[ia]<=B[ib])
 21             {
 22                 C.push_back(A[ia++]);
 23             }else C.push_back(B[ib++]);
 24         }
 25     }else if(flags==0){//降序
 26         while(ia<A.size()&&ib<B.size())
 27         {
 28             if(A[ia]>=B[ib])
 29             {
 30                 C.push_back(A[ia++]);
 31             }else C.push_back(B[ib++]);
 32         }
 33     }
 34     while(ia<A.size())
 35     {
 36         C.push_back(A[ia++]);
 37     }
 38
 39     while(ib<B.size())
 40     {
 41         C.push_back(B[ib++]);
 42     }
 43
 44 }
 45
 46 /*
 47 *将n个长度的子表归并为m个子表（n为偶数，m=n/2;否,m=n/2+1）
 48 */
 49 int Merge_sort(vector<vector<int>>array,int n,vector<vector<int>>&mid,int &count,int flags)
 50 {
 51     int i;
 52     if(n%2==0)
 53     {
 54         count = n/2;
 55         for(i=0;i<n-1;i=i+2)
 56         {
 57             merge(array[i],array[i+1],mid[i/2],flags);
 58         }
 59     }else{
 60         count = n/2 +1;
 61         vector<int>temp;
 62         temp.clear();
 63         for(i=0;i<n-2;i=i+2)
 64         {
 65             merge(array[i],array[i+1],mid[i/2],flags);
 66         }
 67         merge(array[n-1],temp,mid[count-1],flags);
 68     }
 69     return 0;
 70 }
 71
 72 void Sort_Merge()
 73 {
 74     int i,j,flags;
 75     time_t start,end;
 76     vector<int>array;
 77     cout<<"Initialize Array:"<<endl;
 78     for(i=0;i<num;i++)//随机产生数组中的数据
 79     {
 80         array.push_back(rand()%1000);
 81         cout<<setw(5)<<array[i]<<" ";
 82         if((i+1)%10==0)cout<<endl;
 83     }
 84     cout<<endl;
 85     cout<<"please inout flags[flags:1,升序;0降序]:";
 86     cin>>flags;
 87     start = clock();
 88     vector<vector<int>>arraymid(array.size());
 89     for(i=0;i<array.size();i++)//初始化num个子表
 90     {
 91         arraymid[i].push_back(array[i]);
 92     }
 93     vector<vector<int>>mid(num);//存放num个子表归并后的子表
 94     int count =arraymid.size();//用于记录起始子表数目
 95     int countmid = count;//用于记录归并后子表的数目
 96     while(count!=1)
 97     {
 98         for(i=0;i<countmid;i++)
 99         {
100             mid[i].clear();//清空待存放归并后子表的数组
101         }
102         Merge_sort(arraymid,count,mid,countmid,flags);//归并
103
104         for(i=0;i<count;i++)//将归并后的子表赋给arraymid,然后继续归并
105         {
106             arraymid[i].clear();
107             for(j=0;j<mid[i].size();j++)
108             {
109                 arraymid[i].push_back(mid[i][j]);
110             }
111         }
112         count = countmid;//子表数目更新为归并后的子表数目
113     }
114     end = clock();
115     cout<<"The Merge_Sorted Array:"<<endl;
116     //输出最终排序后的的结果
117     for(i=0;i<count;i++)
118     {
119         for(j=0;j<mid[i].size();j++)
120         {
121             cout<<setw(5)<<mid[i][j]<<" ";
122             if((j+1)%10==0)cout<<endl;
123         }
124     }
125     cout<<endl;
126
127     cout<<"performnace time:";
128     cout<<(double)(end - start )/1000<<"Seconds"<<endl;
129 }
130
131 int main()
132 {
133     Sort_Merge();
134     return 0;
135 }