常用排序算法的比较
#include <iostream> #include <vector> #include <random> #include <time.h> using namespace std; /* 2015.5.4 quicksort */ void swap(int &a, int &b) { int temp = a; a = b; b = temp; } //分割取下标 int partition_QuickSort(vector<int>& nums, int begin, int end) { if (nums.size() == 0)return -1; int pivot = nums[begin]; int i = begin+1, j = end; while (i <= j) { while (i <=j&&nums[i] < pivot){ ++i; } while (j>=i&&nums[j] >= pivot){ --j; } if (i <= j) { swap(nums[i++], nums[j--]); } } swap(nums[begin], nums[j]); return j; } void quicksort(vector<int>& nums,int begin,int end) { if (begin >=end)return; int Sortedindex=partition_QuickSort(nums, begin, end); quicksort(nums, begin, Sortedindex - 1); quicksort(nums, Sortedindex + 1, end); } void qsort(vector<int>& nums) { quicksort(nums, 0, nums.size() - 1); } /* endofqsort; */ /* bubblesort 2014.5.4 */ void bubblesort(vector<int> & nums) { for (int i = 1; i < nums.size(); i++) { for (int j = 0; j < nums.size()-i; j++) { if (nums[j]>nums[j + 1])swap(nums[j], nums[j + 1]); } } } /* endof bubblesort */ /* heapsort */ void sink(vector<int>& ATemp, int i)//i 是下沉index { int j = 2 * i + 1; while (j<ATemp.size()) { if (j + 1 < ATemp.size()) { if (ATemp[j] < ATemp[j + 1])++j;//选最da } if (ATemp[i] < ATemp[j]) { auto temp = ATemp[i]; ATemp[i] = ATemp[j]; ATemp[j] = temp; i = j; j = 2 * j + 1; } else break; } } void sink(vector<int>& ATemp, int i,int n)//i 是下沉index { int j = 2 * i + 1; while (j<n) { if (j + 1 < n) { if (ATemp[j] < ATemp[j + 1])++j;//选最da } if (ATemp[i] < ATemp[j]) { auto temp = ATemp[i]; ATemp[i] = ATemp[j]; ATemp[j] = temp; i = j; j = 2 * j + 1; } else break; } } void swim(vector<int>& A, int i) { int j = (i - 1) / 2; while (j >= 0 && i != 0) { if (A[i] > A[j]) { auto temp = A[j]; A[j] = A[i]; A[i] = temp; i = j; j = (j - 1) / 2; } else break; } } void insert(vector<int>& A, int num) { A.push_back(num); swim(A, A.size() - 1); } int deletemax(vector<int> &A) { if (A.size() > 0) { int temp = A[0]; A[0] = A[A.size() - 1]; A.pop_back(); sink(A, 0); return temp; } else { return -1;//errrrrrrrrrrro } } void heapify(vector<int> &A) { for (int i = A.size() / 2 - 1; i >= 0; i--) { sink(A, i); } } void heapsort(vector<int> & nums) { heapify(nums); int N = nums.size(); while (N>0) { swap(nums[0], nums[--N]); sink(nums, 0, N); } } /* end of heapsort */ /*mergesort 2014.5.4 */ void mergesortUtil(vector<int>& nums, int begin, int end) { if (begin >= end)return; mergesortUtil(nums, begin, begin + (end - begin) / 2); mergesortUtil(nums, begin + (end - begin) / 2 + 1, end); int secondbegin = begin + (end - begin) / 2 + 1; int i = begin; int j = secondbegin; vector<int> ans; while (i <= begin + (end - begin) / 2 && j <= end) { if (nums[i] < nums[j]) { ans.push_back(nums[i++]); } else { ans.push_back(nums[j++]); } } while (i == begin + (end - begin) / 2+1&&j<=end) { ans.push_back(nums[j++]); } while (i <= begin + (end - begin) / 2 && j == end+1) { ans.push_back(nums[i++]); } int index = 0; for (int i = begin; i <= end; i++) { nums[i] = ans[index++]; } } void mergesort(vector<int> & nums) { mergesortUtil(nums, 0, nums.size() - 1); } /* endof mergesort */ /* inserctionsort */ void inserctionsort(vector<int> &nums) { for (int i = 1; i < nums.size(); i++) { for (int j = i; j >0&&(nums[j]<nums[j-1]); j--)//nums[i]的信息是从j=i获取的 { swap(nums[j], nums[j - 1]); } } } /* endofinserctionsort */ /* selectionSort */ void selectionsort(vector<int>& nums) { for (int i = 0; i < nums.size(); i++) { int minindex = i; for (int j = i+1; j < nums.size(); j++) { if (nums[minindex] > nums[j])minindex = j; } swap(nums[i], nums[minindex]); } } /* endofSelectionSort */ /* shellsort */ void shellsort(vector<int> & nums) { int N = nums.size(); int h = 1; while (h<N/4) { h = h * 4 + 1; } while (h>=1) { for (int i = h; i < nums.size(); i++) { for (int j = i; j >= h && (nums[j] < nums[j - h]); j -= h) swap(nums[j], nums[j - h]); } h /= 4; } } /* endofshellsort */ bool isordered(vector<int>& nums) { for (size_t i = 0; i < nums.size()-1; i++) { if (nums[i + 1] - nums[i] < 0)return false; } return true; } vector<int> good_randvec(int number) { static default_random_engine e; static uniform_int_distribution<int> u(-2147483648, 2147483647); vector<int> ret; for (size_t i = 0; i < number; i++) { ret.push_back(u(e)); } return ret; } #define SIZE (100000) int main() { auto random_vec = good_randvec(SIZE); int time1 = clock(); inserctionsort(random_vec);//插入 int time2 = clock(); cout << time2 - time1 << endl; cout << isordered(random_vec) << endl; random_vec = good_randvec(SIZE); time1 = clock(); shellsort(random_vec);//希尔 time2 = clock(); cout << time2 - time1 << endl; cout << isordered(random_vec) << endl; random_vec = good_randvec(SIZE); time1 = clock(); selectionsort(random_vec);//选择 time2 = clock(); cout << time2 - time1 << endl; cout << isordered(random_vec) << endl; random_vec = good_randvec(SIZE); time1 = clock(); bubblesort(random_vec);//冒泡 time2 = clock(); cout << time2 - time1 << endl; cout << isordered(random_vec) << endl; random_vec = good_randvec(SIZE); time1 = clock(); qsort(random_vec);//快排 time2 = clock(); cout << time2 - time1 << endl; cout << isordered(random_vec) << endl; random_vec = good_randvec(SIZE); time1 = clock(); heapsort(random_vec);//堆排 time2 = clock(); cout << time2 - time1 << endl; cout << isordered(random_vec) << endl; random_vec = good_randvec(SIZE); time1 = clock(); mergesort(random_vec);//归并 time2 = clock(); cout << time2 - time1 << endl; cout << isordered(random_vec) << endl; system("pause"); return 0; }
10W随机数，下面的O(nlogn)还是很给力的。
