全排列判断栈序火车进出站

Posted 2022-12-04 松狮MVP

1、全排列：

（1）递归实现：

void myFullSort(vector<int> data, int k, int end)

	int i;
	if (k == end)
	
		for (i = 0; i <= end; i++)
		
			cout << data[i] << " ";
		
		cout << endl;
	
	else
	
		for (i = k; i <= end; i++)
		
			std::swap(data[k], data[i]);
			myFullSort(data, k + 1, end);
			std::swap(data[k], data[i]);
		
	

（2）非递归实现：

（3）运用STL中的函数next_permutation( )：

#include <iostream>  
#include <algorithm>  
#include <vector>
using namespace std;

//STL —— next_permutation()
void permutation(vector<int> array, int len)

	sort(array.begin(), array.end());    //必须首先对原始数据进行排序，否则无法得到全部的全排列（）

	do
		for (int i = 0; i < len; ++i)
		
			cout << array[i] << " ";
		
		cout << endl;
	 while (next_permutation(array.begin(), array.end()));    //next_permutation是根据数字大小在找下一个排列


int main()

	vector<int> a =  3, 2, 1, 4 ;

	permutation(a, a.size());

	return 0;

（4）如果数据中有重复数字，则需要剔除重复的全排列序列：

bool IsSwap(vector<int>& pszStr, int nBegin, int nEnd)

	for (int i = nBegin; i < nEnd; i++)
	
		if (pszStr[i] == pszStr[nEnd])
			return false;
	
	return true;


void myFullSort(vector<int> data, int k, int end)

	int i;
	if (k == end)
	
		for (i = 0; i <= end; i++)
		
			cout << data[i] << " ";
		
		cout << endl;
	
	else
	
		for (i = k; i <= end; i++)
		
			if (IsSwap(data, k, i))
			
				std::swap(data[k], data[i]);
				myFullSort(data, k + 1, end);
				std::swap(data[k], data[i]);
			
		
	

2、判断栈序：

bool  isPopsort(vector<int> Push, vector<int> Pop)

	size_t size1 = Push.size();
	size_t size2 = Pop.size();

	if (size1 == 0 || size2 == 0)
		return false;

	stack<int> tmp;   //辅助栈
	for (size_t i = 0, j = 0; i < size1; i++)
	
		tmp.push(Push[i]);//如果不是出栈序列元素，就一直压栈
        
		while (j < size2 && !tmp.empty() && Pop[j] == tmp.top())   //开始判断
		
			tmp.pop();

			j++;
		
	

	return tmp.empty();

3、火车进出站：（上面两者的组合）

#include <iostream>
#include <vector>
#include <stack>
using namespace std;

vector<int> input;

bool  isPopsort1(vector<int> Push, vector<int> Pop)

	size_t size1 = Push.size();
	size_t size2 = Pop.size();

	if (size1 == 0 || size2 == 0)
		return false;

	stack<int> tmp;   //辅助栈
	for (size_t i = 0, j = 0; i < size1; i++)
	
		tmp.push(Push[i]);//如果不是出栈序列元素，就一直压栈

		while (j < size2 && !tmp.empty() && Pop[j] == tmp.top())   //开始判断
		
			tmp.pop();

			j++;
		
	

	return tmp.empty();


void myFullSort1(vector<int> data, int k, int end)

	int i;
	if (k > end)
	
		if (isPopsort1(input, data))       //全排列必须是栈序，才可以输出
		
			for (i = 0; i <= end; i++)
			
				cout << data[i] << " ";
			
			cout << endl;
		

	
	else
	
		for (i = k; i <= end; i++)
		
			std::swap(data[k], data[i]);
			myFullSort1(data, k + 1, end);
			std::swap(data[k], data[i]);
		
	


int main()

	int N;
	cin >> N;

	for (int i = 0; i < N; i++)
	
		int tmp;
		cin >> tmp;
		input.push_back(tmp);
	

	myFullSort1(input, 0, N - 1);

	return 0;