排序演算法（C++實現）

標籤：

  1 #include <vector>  2 using std::vector;  3   4 template<typename T>  5 void swap(vector<T> &a, int i, int j)  6 {  7     T tmp = a[i];  8     a[i] = a[j];  9     a[j] = tmp; 10 } 11  12 //簡單插入排序 13 template<typename T> 14 void insertionSort(vector<T> &a) 15 { 16     for(int p=1; p!=a.size(); ++p) 17     { 18         int tmp = a[p], j; 19         for(j = p; j>0&&a[j-1]>tmp; --j) 20             a[j] = a[j-1]; 21         a[j] = tmp; 22     } 23 } 24  25 //堆排序 26 //把將要進行排序的元素依次入堆，再逐個彈出，便得到排好序的元素序列。 27 //堆的C++實現：http://www.cnblogs.com/pczhou/p/4648146.html 28  29 //歸併排序 30 template<typename T> 31 void mergeSort(vector<T> &a) 32 { 33     vector<T> tmpA(a.size()); 34     mergeSort(a, tmpA, 0, a.size()-1); 35 } 36 template<typename T> 37 void mergeSort(vector<T> &a, vector<T> &tmpA, int left, int right) 38 { 39     if(left<right) 40     { 41         int mid = (left+right)/2; 42         mergeSort(a, tmpA, left, mid); 43         mergeSort(a, tmpA, mid+1, right); 44         merge(a, tmpA, left, mid+1, right); 45     } 46 } 47 template<typename T> 48 void merge(vector<T> &a, vector<T> &tmpA, int leftPos, int rightPos, int rightEnd) 49 { 50     int leftEnd = rightPos-1, tmpPos = leftPos; 51     int numElements = rightEnd-leftPos+1; 52  53     while(leftPos<=leftEnd&&rightPos<=rightEnd) 54     { 55         if(a[leftPos]<a[rightPos]) 56             tmpA[tmpPos++] = a[leftPos++]; 57         else 58             tmpA[tmpPos++] = a[rightPos++]; 59     } 60     while(leftPos<=leftEnd) 61         tmpA[tmpPos++] = a[leftPos++]; 62     while(rightPos<=rightEnd) 63         tmpA[tmpPos++] = a[rightPos++]; 64     for(; numElements; --numElements, --rightEnd) 65         a[rightEnd] = tmpA[rightEnd]; 66 } 67  68 //快速排序 69 //（採用三數中值分割法確定樞紐元） 70 template<typename T> 71 void quickSort(vector<T> &a) 72 { 73     quickSort(a, 0, a.size()-1); 74 } 75 template<typename T> 76 const T& median3(vector<T> &a, int left, int right) 77 { 78     int mid = (left+right)/2; 79     if(a[left]<a[mid]&&a[mid]<a[right]||a[right]<a[mid]&&a[mid]<a[left]) 80         swap(a, mid, right); 81     else if(a[mid]<a[left]&&a[left]<a[right]||a[right]<a[left]&&a[left]<a[mid]) 82         swap(a, left, right); 83     return a[right]; 84 } 85 template<typename T> 86 void quickSort(vector<T> &a, int left, int right) 87 { 88     if(left<right) 89     { 90         T pivot = median3(a, left, right); 91         int i=left-1, j=left; 92         for(; j<right; ++j) 93         { 94             if(a[j]<pivot) 95             { 96                 ++i; 97                 swap(a, i, j); 98             } 99         }100         swap(a, i+1, right);101 102         quickSort(a, left, i);103         quickSort(a, i+2, right);104     }105 }106 107 //桶排序108 //假設：所有輸入資料均為非負，且不超過M109 const int M = 100;110 void bucketSort(vector<int> &a)111 {112     vector<int> count(M+1);113     for(int i=0; i!=count.size(); ++i) count[i] = 0;114     for(int i=0; i!=a.size(); ++i) ++count[a[i]];115     int k = 0;116     for(int i=0; i!=count.size(); ++i)117         for(int j=0; j<count[i]; ++j)   a[k++] = i;118 }

測試代碼:

 1     vector<int> a1, a2, a3, a4; 2     for(int i=0; i<10; ++i) 3     { 4         int tmp; 5         cout<<"please input: "; 6         cin>>tmp; 7         a1.push_back(tmp); 8         a2.push_back(tmp); 9         a3.push_back(tmp);10         a4.push_back(tmp);11     }12     insertionSort(a1);13     mergeSort(a2);14     quickSort(a3);15     bucketSort(a4);16     cout<<"insertion sort:"<<endl;17     for(int i=0; i!=a1.size(); ++i)18         cout<<" "<<a1[i];19     cout<<endl;20     cout<<"merge sort:"<<endl;21     for(int i=0; i!=a2.size(); ++i)22         cout<<" "<<a2[i];23     cout<<endl;24     cout<<"quick sort:"<<endl;25     for(int i=0; i!=a3.size(); ++i)26         cout<<" "<<a3[i];27     cout<<endl;28     cout<<"bucket sort:"<<endl;29     for(int i=0; i!=a4.size(); ++i)30         cout<<" "<<a4[i];31     cout<<endl;

測試結果：

排序演算法（C++實現）