全排列算法实现

今天跟同事讨论到全排列算法，即n个数任意排列，但不能有重复的数，将所有的排列列出。

 

#include "stdafx.h"#include <iostream>#include <vector>using namespace std;template<class T>void swap(T *a, T *b){T t = *a;*a = *b;*b = t;}template<class T>void Permutation(vector<T> &data, typename vector<T>::size_type start, typename vector<T>::size_type length){// The base condition, that is we reach the last data.// So we print out the the current permulation.if (1 == length){Print(data);}else{// Print out the permulation befor swaping with its next ones.Permutation(data, start + 1, length - 1);// Swaping through from the next to the last one.for (typename vector<T>::size_type i = 1; i < length; i++){swap(&data[start], &data[start + i]);Permutation(data, start + 1, length - 1);// Swap back to keep the data order for its out caller.swap(&data[start + i], &data[start]);}}}static long nNum;template<class T>void Print(const vector<T> &data){// Why the following block can not be compiled successfully under VS 2005./*for (typename vector<T>::iterator it = data.begin(); it != data.end(); it++){cout << *it;}*/for (typename vector<T>::size_type i = 0; i < data.size(); i++){cout << data[i];}cout << endl;nNum++;}int _tmain(int argc, _TCHAR* argv[]){vector<char> data;data.push_back('a');data.push_back('b');data.push_back('c');data.push_back('d');Permutation(data, 0, data.size());cout << nNum << endl;int wait;cin >> wait;return 0;}#if 0void permutation(char data[], long start, long len){// The base condition, that is we reach the last data.// So we print out the the current permulation.if (1 == len){printf("%s", data);printf("/n");}else{// Print out the permulation befor swaping with its next one.permutation(data, start + 1, len - 1);// Swaping through from the next to the last one.for (long i = 1; i < len; i++){swap(data[start], data[start + i]);permutation(data, start + 1, len - 1);// Swap back to keep the data order for it out caller.swap(data[start + i], data[start]);}}}int _tmain(int argc, _TCHAR* argv[]){char data[] = "abc";permutation(data, 0, 3);int wait;cin >> wait;return 0;}#endif

参考文章：http://www.cnblogs.com/nokiaguy/archive/2008/05/11/1191914.html