algorithm/Week_04/id_140/Leetcode_784_140.java at master · feixiangcode/algorithm · GitHub

53 lines (44 loc) · 1.27 KB

import java.util.ArrayList;

import java.util.LinkedList;

import java.util.List;

/**

* Given a string S, we can transform every letter individually to be lowercase or uppercase to create another string. Return a list of all possible strings we could create.

* Examples:

* Input: S = "a1b2"

* Output: ["a1b2", "a1B2", "A1b2", "A1B2"]

* Input: S = "3z4"

* Output: ["3z4", "3Z4"]

* Input: S = "12345"

* Output: ["12345"]

* Note:

* S will be a string with length between 1 and 12.

* S will consist only of letters or digits.

public class Leetcode_784_140 {

public List<String> letterCasePermutation(String S) {

List<String> s = new ArrayList<String>();

if (S == null) {

return new LinkedList<>();

}

util(S.toCharArray(), s, 0);

return s;

}

public void util(char[] c_arr, List<String> s, int index) {

if(index == c_arr.length) {

s.add(new String(c_arr));

return;

}

if(Character.isDigit(c_arr[index])) {

util(c_arr,s,index+1);

return;

}

c_arr[index] = Character.toLowerCase(c_arr[index]);

util(c_arr,s, index+1);

c_arr[index] = Character.toUpperCase(c_arr[index]);

util(c_arr,s,index+1);

}

algorithm/Week_04/id_140/Leetcode_784_140.java at master · feixiangcode/algorithm · GitHub

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