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LetterCasePermutation0784.java
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43 lines (34 loc) · 1.07 KB
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import java.util.ArrayList;
import java.util.List;
/**
* ×Öĸ´óСдȫÅÅÁÐ
*/
public class LetterCasePermutation0784{
public static void main(String[] args) {
letterCasePermutation("a1B2");
}
public static List<String> result = new ArrayList<>();
public static List<String> letterCasePermutation(String S) {
backtrack(S, 0, "");
for (String str : result) {
System.out.println(str);
}
return result;
}
private static void backtrack(String s, int start, String sb) {
if (start >= s.length()) {
System.out.println(sb.toString());
return;
}
char ch = s.charAt(start);
if (Character.isLowerCase(ch)) {
backtrack(s, start+1, sb + ch);
backtrack(s, start+1, sb + Character.toUpperCase(ch) );
}else if (Character.isUpperCase(ch)) {
backtrack(s, start+1, sb + ch);
backtrack(s, start+1, sb + Character.toLowerCase(ch));
}else {
backtrack(s, start+1, sb + ch);
}
}
}