fork download
copy 
  1. #include <stdio.h>
  2. #include <string.h>
  3. #include <stdlib.h>
  4.  
  5. // Function to compare strings lexicographically for sorting
  6. int compare(const void *a, const void *b) {
  7.     return strcmp((char *)a, (char *)b);
  8. }
  9.  
  10. // Function to generate the next lexicographical permutation
  11. int next_permutation(char *str) {
  12.     int i = strlen(str) - 1;
  13.  
  14.     // Step 1: Find the rightmost character which is smaller than the next character
  15.     while (i > 0 && str[i - 1] >= str[i]) {
  16.         i--;
  17.     }
  18.  
  19.     // Step 2: If there is no such character, we've generated all permutations
  20.     if (i == 0) {
  21.         return 0;
  22.     }
  23.  
  24.     // Step 3: Find the character to swap with (next larger character to the right)
  25.     int j = strlen(str) - 1;
  26.     while (str[j] <= str[i - 1]) {
  27.         j--;
  28.     }
  29.  
  30.     // Step 4: Swap the characters
  31.     char temp = str[i - 1];
  32.     str[i - 1] = str[j];
  33.     str[j] = temp;
  34.  
  35.     // Step 5: Reverse the suffix
  36.     j = strlen(str) - 1;
  37.     while (i < j) {
  38.         temp = str[i];
  39.         str[i] = str[j];
  40.         str[j] = temp;
  41.         i++;
  42.         j--;
  43.     }
  44.  
  45.     return 1;
  46. }
  47.  
  48. void generatePermutations(char *str) {
  49.     // Sort the string to get the first permutation in lexicographical order
  50.     qsort(str, strlen(str), sizeof(char), compare);
  51.  
  52.     // Print the first permutation
  53.     printf("%s ", str);
  54.  
  55.     // Generate and print the next permutations until no more are possible
  56.     while (next_permutation(str)) {
  57.         printf("%s ", str);
  58.     }
  59.  
  60.     printf("\n");
  61. }
  62.  
  63. int main() {
  64.     int T;
  65.     scanf("%d", &T);  // Read number of test cases
  66.  
  67.     while (T--) {
  68.         char str[6];  // Only up to 5 characters are allowed
  69.         scanf("%s", str);  // Read the string
  70.         generatePermutations(str);  // Generate and print permutations
  71.     }
  72.  
  73.     return 0;
  74. }
  75.  
Success #stdin #stdout 0.01s 5268KB
comments (?)
stdin
copy 
2
acb
sad
stdout
copy 
abc acb bac bca cab cba 
ads asd das dsa sad sda
https://ideone.com/exCLI7
language:
C (gcc 8.3)
created:
3 days ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!