leetcode784字母大小写全排列

huang · huang · commit a933f6759b4a · 2019-11-08T10:37:40.000+08:00
diff --git a/leetcode/LetterCasePermutation0784.java b/leetcode/LetterCasePermutation0784.java
@@ -0,0 +1,43 @@
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * ��ĸ��Сдȫ����
+ */
+
+ 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);
+        }
+    }
+    
+ }
