Description
You are to write a program that has to generate all possible words from a given set of letters.
Example: Given the word "abc", your program should - by
exploring all different combination of the three letters - output the
words "abc", "acb", "bac", "bca", "cab" and "cba".
In the word taken from the input file, some letters may
appear more than once. For a given word, your program should not produce
the same word more than once, and the words should be output in
alphabetically ascending order.
Input
The input consists of several words. The first line contains a number
giving the number of words to follow. Each following line contains one
word. A word consists of uppercase or lowercase letters from A to Z.
Uppercase and lowercase letters are to be considered different. The
length of each word is less than 13.
Output
For each word in the input, the output should contain all different
words that can be generated with the letters of the given word. The
words generated from the same input word should be output in
alphabetically ascending order. An upper case letter goes before the
corresponding lower case letter.
Sample Input
3 aAb abc acba
Sample Output
Aab Aba aAb abA bAa baA abc acb bac bca cab cba aabc aacb abac abca acab acba baac baca bcaa caab caba cbaa
Hint
An upper case letter goes before the corresponding lower case letter.
So the right order of letters is ‘A‘<‘a‘<‘B‘<‘b‘<...<‘Z‘<‘z‘.
STL的全排列问题，写好排序方案，直接调用 next_permutation（）函数便可！
#include <cstdio>
#include <string>
#include <cstring>
#include <algorithm>
using namespace std;
int n;
char str[15];
bool cmp(char a,char b)
{
if(tolower(a)==tolower(b))
return a<b;
else
return tolower(a)<tolower(b);
}
int main()
{
scanf("%d",&T);
while( T-- )
{
scanf("%s",str);
sort(str,str+strlen(str),cmp);//自定义排序
do
{
cout << str << endl ;
}while(next_permutation(str,str+strlen(str),cmp));
}
return 0;
}