排序

请原谅我，上来就是在大家眼中水的1B的冒泡排序

可是我相信冒泡排序也是大家看到算法--排序这个大家庭的第一朵鲜花了

 冒泡排序

/*冒泡排序法 容易实现，但是要进行所有轮的比较，运行速度较慢*/#include<iostream>using namespace std;void bubble(int*,int);void main(){int array[]={5,4,6,8,9,3,1,2,7};const int len=sizeof(array)/sizeof(int);for(int i=0;i<len;++i)cout<<array[i]<<" ";cout<<endl;bubble(array,len);}void bubble(int*a,int size){//数组名会自动转化为指向第一个元素的指针，虽然不能直接传递数组，但函数的形参可以写成数组的形式（int*，int[]，int[10]）形参类型都是int*int i,temp;for(int pass=1;pass<size;++pass){for(i=0;i<size-pass;++i)if(a[i]>a[i+1]){temp=a[i];a[i]=a[i+1];a[i+1]=temp;}for(i=0;i<size;++i)cout<<a[i]<<" ";cout<<endl;}}

快速排序

快速排序可谓是排序大家族中的姣姣者

#include<iostream>#include<vector>using namespace std;int pivotIndex(vector<int>&v, int first, int last){// index for the midpoint of [first,last) and the// indices that scan the index range in tandemint mid, scanUp, scanDown;// pivot value and object used for exchangesint pivot, temp;if (first == last)return last;else if (first == last-1)return first;else{mid = (last + first)/2;pivot = v[mid];// exchange the pivot and the low end of the range// and initialize the indices scanUp and scanDown.v[mid] = v[first];v[first] = pivot;scanUp = first + 1;scanDown = last - 1;// manage the indices to locate elements that are in// the wrong sublist; stop when scanDown <= scanUpfor(;;){// move up lower sublist; stop when scanUp enters// upper sublist or identifies an element >= pivotwhile (scanUp <= scanDown && v[scanUp] < pivot)scanUp++;// scan down upper sublist; stop when scanDown locates// an element <= pivot; we guarantee we stop at arr[first]while (pivot < v[scanDown])scanDown--;// if indices are not in their sublists, partition completeif (scanUp >= scanDown)break;// indices are still in their sublists and identify// two elements in wrong sublists. exchangetemp = v[scanUp];v[scanUp] = v[scanDown];v[scanDown] = temp;scanUp++;scanDown--;}// copy pivot to index (scanDown) that partitions sublists// and return scanDownv[first] = v[scanDown];v[scanDown] = pivot;return scanDown;}}void quicksort(vector<int>& v, int first, int last){   // index of the pivot   int pivotLoc;// temp used for an exchange when [first,last) has// two elementsint temp;   // if the range is not at least two elements, return   if (last - first <= 1)return;// if sublist has two elements, compare v[first] and// v[last-1] and exchange if necessary   else if (last - first == 2){if (v[last-1] < v[first]){temp = v[last-1];v[last-1] = v[first];v[first] = temp;}return;}   else{pivotLoc = pivotIndex(v, first, last);// make the recursive callquicksort(v, first, pivotLoc);// make the recursive callquicksort(v, pivotLoc +1, last);}}int main(){vector<int>ivec;int array[]={2,4,5,6,78,88,34,32,43,24,23,43,24,23,4,23,484};int length=sizeof(array)/sizeof(int);for(int i =0 ;i<length;++i)ivec.push_back(array[i]);quicksort(ivec,0,length);for(i =0 ;i<length;++i)cout<<ivec[i]<<" ";}

基数排序

想象第一次知道的不基于比较的排序，我记得我当时就直接“震惊了”

#include<iostream>#include<queue>#include<vector>#include "time.h";using namespace std;void distribute(const vector<int>& v, queue<int> digitQueue[],                int power){int i;// loop through the vector, inserting each element into// the queue (v[i] / power) % 10for (i = 0; i < v.size(); i++)digitQueue[(v[i] / power) % 10].push(v[i]);}// support function for radixSort()// gather elements from the queues and copy back to the vectorvoid collect(queue<int> digitQueue[], vector<int>& v){int i = 0, digit;// scan the vector of queues using indices 0, 1, 2, etc.for (digit = 0; digit < 10; digit++)// collect items until queue empty and copy items back// to the vectorwhile (!digitQueue[digit].empty()){v[i] = digitQueue[digit].front();digitQueue[digit].pop();i++;}}void radixSort(vector<int>& v, int d){int i;int power = 1;queue<int> digitQueue[10];for (i=0;i < d;i++){distribute(v, digitQueue, power);collect(digitQueue, v);power *= 10;}}void main(){vector<int>ivec;int i;srand(time(NULL));for(i=0;i<20;++i){ivec.push_back(rand()%20);}radixSort(ivec,2);for(i=0; i<ivec.size();++i){cout<<ivec[i]<<" ";if((i+1)%5==0)cout<<endl;}cout<<endl;}

归并排序

 

#include<iostream>#include<vector>using namespace std;template <typename T>void merge(vector<T>& v, int first, int mid, int last){// temporary vector to merge the sorted sublistsvector<T> tempVector;int indexA, indexB, indexV;// set indexA to scan sublistA (index range [first,mid)// and indexB to scan sublistB (index range [mid, last)indexA = first;indexB = mid;// while both sublists are not exhausted, compare v[indexA] and// v[indexB]copy the smaller to vector temp using push_back()while (indexA < mid && indexB < last)if (v[indexA] < v[indexB]){tempVector.push_back(v[indexA]);// copy element to tempindexA++;// increment indexA}else{tempVector.push_back(v[indexB]);// copy element to tempindexB++;// increment indexB}// copy the tail of the sublist that is not exhaustedwhile (indexA < mid){tempVector.push_back(v[indexA]);indexA++;}while (indexB < last){tempVector.push_back(v[indexB]);indexB++;}// copy vector tempVector using indexV to vector v using indexA// which is initially set to firstindexA = first;// copy elements from temporary vector to original listfor (indexV = 0; indexV < tempVector.size(); indexV++){v[indexA] = tempVector [indexV];indexA++;}}// sorts v in the index range [first,last) by merging// ordered subliststemplate <typename T>void mergeSort(vector<T>& v, int first, int last){// if the sublist has more than 1 element continueif (first + 1 < last)  {// for sublists of size 2 or more, call mergeSort()// for the left and right sublists and then// merge the sorted sublists using merge()int midpt = (last + first) / 2;mergeSort(v, first, midpt);mergeSort(v, midpt, last);merge(v, first, midpt, last);   }}int main(){vector<int> ivec;int array[]={1,2,3,4,5,8,9,7,1,5,2,54,544,54,45,4,5,4,454,45,45,44,54,4,34,2,256,34,926};int length=sizeof(array)/sizeof(int);for(int i=0;i<length;++i){ivec.push_back(array[i]);}mergeSort(ivec,0,length);for(i=0;i<length;++i){cout<<ivec[i]<<" ";}return 0;}

 

鸽巢排序（来自C++版块精华帖）

排序字节串、宽字节串最快的排序算法，计数排序的变种（将计数缓冲区大小固定，少一次遍历开销），速度是STL中std::sort的20多倍，更重要的是实现极其简单！缺点是需要一个size至少等于待排序数组取值范围的缓冲区，不适合int等大范围数据

#include<iostream>#include"time.h"using namespace std;//鸽巢排序void PigeonholeSort(int *array,int length){int b[256]={0};int i,j,k;for(i=0;i<length;i++)b[array[i]]++;for(i=0,j=0;i<256;i++)for(k=0;k<b[i];k++)array[j++]=i;}void main(){/*time_t nowtime;nowtime=time(NULL);cout<<nowtime;*/int array[]={2,5,6,4,1,9,8,7};int length=sizeof(array)/sizeof(int);PigeonholeSort(array,length);for(int m=0; m !=length; ++m)cout<<array[m]<<" ";}

 

 先附上好东西一个

冒泡和选择排序该被踢出教材了

这是C++版块关于排序的一个精华帖，很不错的的说

 

今天写不完了，明天继续。

 

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