UVa-10098-Generating Fast

AOAPC I: Beginning Algorithm Contests (Rujia Liu) :: Volume 3. Brute Force :: Elementary Skills

 

// 10098 - Generating Fast
#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;
int main(void)
{
	int i, n, len;
	char s[11];
	while(cin >> n)
	while(n--)
	{
		cin >> s;
		len = strlen(s);
		sort(s, s+len);
		do{
			for(i=0; i<len; i++)
				cout << s[i];
			cout << endl;
		}while(next_permutation(s, s+len));
		cout << endl;
	}
	return 0;
}

 

Time limit exceeded：

// 10098 - Generating Fast
#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;

void print_permutation(int cur, int n, char* s, char p, char q)
{
	int i, j;
	char ch;
	if(cur == n)
	{
		for(i=0; i<n; i++)
			cout << s[i];
		cout << endl;
	}
	else
	{
		for(ch=p; ch<=q; ch++)
		{
			int ok = 1;
			for(j=0; j<cur; j++)
				if(s[j] == ch)
					ok = 0;
			if(ok)
			{
				s[cur] = ch;
				print_permutation(cur+1, n, s, p, q);
			}
		}
	}
}

int main(void)
{
	int n, len;
	char s[11];
	while(cin >> n)
	while(n--)
	{
		cin >> s;
		len = strlen(s);
		sort(s, s+len);
		print_permutation(0, len, s, s[0], s[len-1]);
		cout << endl;
	}
	return 0;
}