C语言基础

递归、迭代、循环、查找、排序

0001 求26个字母的全排列

That's a tough question but thankfully, our team is on it. Please bear with us while we're investigating.

#include <stdio.h>
#include <iostream>
using namespace std;
#define N 10
include
#include <stdio.h>
using namespace std;
 
int n;
char a[] = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w',
'x','y','z'};
int ​count=0;
 
void swap(int x,int y)
{
	int tmp;
	tmp = a[x];
	a[x] = a[y];
	a[y] = tmp;
}
 
void search(int k)
{
	int i;
	
	if(k == n)
	{	
		for(i = 0;i < n;i++)
		{
			cout << a[i];
			
		}
		++count;

		cout << endl;
	}
	else
	{
		for(i = k;i < n;i++)
		{
			swap(i,k);
			search(k+1);
			swap(i,k);
		}
		
	}
		
	
}
 
int main()
{
	cin >> n;
	search(0);
	printf("共%d种",count); 

	return 0;
}

此题的思路很简单。对于一个不含重复元素的全排列，使用递归划分，第一次{a}search（0，0）自己与自己排列看成已排列好，第二次{a,b},search(c),以此类推，直到只剩一个，表示已经排好，然后从头开始排列{a,c},search(b)……

Have you had a chance to answer the previous question?

Yes, after a few months we finally found the answer. Sadly, Mike is on vacations right now so I'm afraid we are not able to provide the answer at this point.