Created
August 24, 2016 23:15
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| #include <stdio.h> | |
| #include <string.h> | |
| static const size_t LETTERS = 26; | |
| void permutations(char *str, size_t idx, size_t size, char *letters) | |
| { | |
| if (idx == size) { | |
| printf("%s\n", str); | |
| return; | |
| } | |
| for (size_t i = 0; i < LETTERS; i++) { | |
| if (!letters[i]) | |
| continue; | |
| str[idx] = i + 'a'; | |
| letters[i]--; | |
| permutations(str, idx + 1, size, letters); | |
| letters[i]++; | |
| } | |
| } | |
| void permutation(const char *str) | |
| { | |
| size_t size = strlen(str); | |
| char result[size + 1]; | |
| result[size] = '\0'; | |
| static char letters[LETTERS]; | |
| //memset(letters, 0, sizeof(letters)); | |
| for (size_t i = 0; i < size; i++) { | |
| letters[str[i] - 'a']++; | |
| } | |
| permutations(result, 0, size, letters); | |
| } | |
| int main() | |
| { | |
| const char *str = "abc"; | |
| permutation(str); | |
| } |
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