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    1. // Author: Ashis Kumar Chanda 
    2. // CSE, DU
    3.  
    4. //An upper case letter goes before the corresponding lower case letter.
    5. //  special case:  input  wArZB
    6. //                output  ABZrw is wrong.  it will  ABrwZ
    7.  
    8. //  we need to sort:  guess char as in that order
    9. //      A B C       a b c
    10. //      0 2 4       1 3 5
    11.  
    12.  
    13. #include<iostream>
    14. #include<algorithm>
    15. #include<stdio.h>
    16. #include<string.h>
    17. using namespace std;
    18.  
    19. int value[127];
    20. struct cmp {
    21.     bool operator()(int x, int y) {
    22.         return value[x] < value[y];
    23.     }
    24. };
    25.  
    26. int main()
    27. {
    28. 	int i,k, t;
    29. 	char str[1009];
    30.  
    31. 	for(k = 'A', i=0; k <= 'Z' ; ++k,++i){
    32.         value[k] = i;
    33.         value[k+32] = ++i;
    34.     }
    35.  
    36.     scanf("%d", &t);
    37.     while(t--){
    38.         scanf("%s",str);
    39.         k= strlen( str);
    40.         sort( str, str+k, cmp() );
    41.  
    42.         do{
    43.             printf("%s\n", str);
    44.         }while( next_permutation( str, str+ k, cmp() ) );
    45.     }// next permutation also work at ascending order, so we add  cmp  where also
    46. 	return 0;
    47. }