Generating permutation has always been an important problem in computer science. In this problem you will have to generate the permutation of a given string in ascending order. Remember that your algorithm must be efficient.
Input
The first line of the input contains an integer n, which indicates how many strings to follow. The next n lines contain n strings. Strings will only contain alpha numerals and never contain any space. The maximum length of the string is 10.
Output
For each input string print all the permutations possible in ascending order. Not that the strings should be treated, as case sensitive strings and no permutation should be repeated. A blank line should follow each output set.
Sample Input
3
ab
abc
bca
Sample Output
ab
ba
abc
acb
bac
bca
cab
cba
abc
acb
bac
bca
cab
cba
直接调用库函数next_permutation,在调用前要用qsort先排序下
#define RUN #ifdef RUN #include <stdio.h> #include <stdlib.h> #include <string.h> #include <assert.h> #include <string> #include <iostream> #include <sstream> #include <map> #include <set> #include <vector> #include <list> #include <cctype> #include <algorithm> #include <utility> #include <math.h> #include <ctime> using namespace std; #define MAXN 110 char buf[MAXN]; int cmp( const void *a , const void *b ) { return *(char *)a - *(char *)b; } int main(){ #ifndef ONLINE_JUDGE freopen("10098.in", "r", stdin); freopen("out.out", "w", stdout); #endif int n; scanf("%d", &n); while(n--){ memset(buf, 0, sizeof(buf)); scanf("%s", buf); qsort(buf, strlen(buf), sizeof(buf[0]), cmp); do { printf("%s\n", buf); } while ( next_permutation(buf, buf+strlen(buf)) ); printf("\n"); } } #endif