Algorithm to get all possible string combinations from array up to certain length
What is the best algorithm to get all possible string combinations from a given array with a minimum & maximum length value.
Note: This adds complexity since the
-
I'd go with recursive solution.
"Guess" what is the first element, and recurse on the following elements.
Repeat for all possible guesses.pseudo code:
findCombinations(array, candidate, length): //base clause: if (candidate.length == length): return for each i from 0to array.length: //i is the next char to add candidate.append(array[i]) //print the candidate, since it is a unique permutation smaller then length: print candidate //recursively find permutations for the remianing elements findCombinations(array,candidate,length) //clean up candidate.removeLasElement()Java Code:
private static void findCombinations(char[] array, StringBuilder candidate, int length) { //base clause: if (candidate.length() == length) return; for (int i = 0; i < array.length; i++) { //i is the next char to add candidate.append(array[i]); //print the candidate, since it is a unique permutation smaller then length: System.out.println(candidate); //recursively find permutations for the remianing elements findCombinations(array,candidate,length); //clean up candidate.deleteCharAt(candidate.length()-1); } } public static void findCombinations(char[] array,int length) { findCombinations(array, new StringBuilder(), length); }Invoking:
char[] arr = "abcde".toCharArray(); findCombinations(arr, 3);results in:
a aa aaa aab aac aad aae ab aba abb abc abd abe ac aca acb acc acd ace ad ada adb adc add ade ae aea aeb aec aed aee b ba baa bab bac bad bae bb bba bbb bbc bbd bbe bc bca bcb bcc bcd bce bd bda bdb bdc bdd bde be bea beb bec bed bee c ca caa cab cac cad cae cb cba cbb cbc cbd cbe cc cca ccb ccc ccd cce cd cda cdb cdc cdd cde ce cea ceb cec ced cee d da daa dab dac dad dae db dba dbb dbc dbd dbe dc dca dcb dcc dcd dce dd dda ddb ddc ffffd dde de dea deb dec ded dee e ea eaa eab eac ead eae eb eba ebb ebc ebd ebe ec eca ecb ecc ecd ece ed eda edb edc edd ede ee eea eeb eec eed eee
加载中...
- 热议问题