algorithm/Week_04/id_30/LeetCode_784_30.java at master · feixiangcode/algorithm · GitHub

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package com.shufeng.algorithm4.demo;

import java.util.ArrayList;

import java.util.List;

/**

* @author gsf

* @date 2019-05-12 10:04

public class LeetCode_784_30 {

public static void main(String[] args) {

String str = "a1b2";

// char c = 'A';

// System.out.println((int) c);

// System.out.println(c);

List<String> list = letterCasePermutation(str);

System.out.println(list);

}

public static List<String> letterCasePermutation(String S) {

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

char[] chars = S.toCharArray();

letterCasePermutation(list, chars, "");

return list;

}

public static void letterCasePermutation(List<String> list, char[] chars, String str) {

if (chars.length == str.length()) {

list.add(str);

return;

}

char c = chars[str.length()];

String s = String.valueOf(c);

if (c >= 'A' && c <= 'z') {

letterCasePermutation(list, chars, str + s.toLowerCase());

letterCasePermutation(list, chars, str + s.toUpperCase());

} else {

letterCasePermutation(list, chars, str + s);

}

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