Leetcode/src/main/java/com/fishercoder/solutions/_784.java at master · Saad2012/Leetcode · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
package com.fishercoder.solutions;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

public class _784 {
    public static class Solution1 {
        public List<String> letterCasePermutation(String S) {
            Set<String> result = new HashSet<>();
            result.add(S);
            for (int i = 0; i < S.length(); i++) {
                if (Character.isAlphabetic(S.charAt(i))) {
                    Set<String> newResult = new HashSet<>();
                    for (String word : result) {
                        if (Character.isUpperCase(word.charAt(i))) {
                            StringBuilder sb = new StringBuilder();
                            for (int j = 0; j < i; j++) {
                                sb.append(word.charAt(j));
                            }
                            sb.append(Character.toLowerCase(word.charAt(i)));
                            for (int j = i + 1; j < word.length(); j++) {
                                sb.append(word.charAt(j));
                            }
                            newResult.add(sb.toString());
                        } else {
                            StringBuilder sb = new StringBuilder();
                            for (int j = 0; j < i; j++) {
                                sb.append(word.charAt(j));
                            }
                            sb.append(Character.toUpperCase(word.charAt(i)));
                            for (int j = i + 1; j < word.length(); j++) {
                                sb.append(word.charAt(j));
                            }
                            newResult.add(sb.toString());
                        }
                    }
                    result.addAll(newResult);
                }
            }
            return new ArrayList<>(result);
        }
    }
}