update 784

Author: fishercoder1534

build.gradle

@@ -27,6 +27,7 @@ dependencies {
     compile 'junit:junit:4.13'
     compile group: 'org.apache.commons', name: 'commons-collections4', version: '4.0'
     testCompile group: 'junit', name: 'junit', version:'4.13'
+    testCompile("org.assertj:assertj-core:3.11.1")
 
     compileOnly 'org.projectlombok:lombok:1.18.12'
     annotationProcessor 'org.projectlombok:lombok:1.18.12'

src/main/java/com/fishercoder/solutions/_784.java

@@ -42,4 +42,39 @@ public List<String> letterCasePermutation(String S) {
             return new ArrayList<>(result);
         }
     }
+
+    public static class Solution2 {
+        /**
+         * My completely original solution on 10/11/2021.
+         */
+        public List<String> letterCasePermutation(String s) {
+            List<String> ans = new ArrayList<>();
+            ans.add("");
+            return recursion(s, ans, 0);
+        }
+
+        private List<String> recursion(String s, List<String> ans, int start) {
+            if (start >= s.length()) {
+                return ans;
+            }
+            List<String> newList = new ArrayList<>();
+            int index = start;
+            while (start < s.length() && Character.isDigit(s.charAt(start))) {
+                start++;
+            }
+            String digits = "";
+            if (start > index) {
+                digits = s.substring(index, start);
+            }
+            for (String str : ans) {
+                if (start < s.length()) {
+                    newList.add(str + digits + Character.toUpperCase(s.charAt(start)));
+                    newList.add(str + digits + Character.toLowerCase(s.charAt(start)));
+                } else {
+                    newList.add(str + digits);
+                }
+            }
+            return recursion(s, newList, start + 1);
+        }
+    }
 }

src/test/java/com/fishercoder/_784Test.java

@@ -1,37 +1,44 @@
 package com.fishercoder;
 
 import com.fishercoder.solutions._784;
+
 import java.util.Arrays;
 import java.util.List;
+
 import org.junit.BeforeClass;
 import org.junit.Test;
 
-import static org.junit.Assert.assertEquals;
+import static org.assertj.core.api.Assertions.assertThat;
 
 public class _784Test {
-  private static _784.Solution1 solution1;
-  private static List<String> expected;
-
-  @BeforeClass
-  public static void setup() {
-    solution1 = new _784.Solution1();
-  }
-
-  @Test
-  public void test1() {
-    expected = Arrays.asList("a1b2", "a1B2", "A1b2", "A1B2");
-    assertEquals(expected, solution1.letterCasePermutation("a1b2"));
-  }
-
-  @Test
-  public void test2() {
-    expected = Arrays.asList("3z4", "3Z4");
-    assertEquals(expected, solution1.letterCasePermutation("3z4"));
-  }
-
-  @Test
-  public void test3() {
-    expected = Arrays.asList("12345");
-    assertEquals(expected, solution1.letterCasePermutation("12345"));
-  }
+    private static _784.Solution1 solution1;
+    private static _784.Solution2 solution2;
+    private static List<String> expected;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _784.Solution1();
+        solution2 = new _784.Solution2();
+    }
+
+    @Test
+    public void test1() {
+        expected = Arrays.asList("a1b2", "a1B2", "A1b2", "A1B2");
+        assertThat(expected).hasSameElementsAs(solution1.letterCasePermutation("a1b2"));
+        assertThat(expected).hasSameElementsAs(solution2.letterCasePermutation("a1b2"));
+    }
+
+    @Test
+    public void test2() {
+        expected = Arrays.asList("3z4", "3Z4");
+        assertThat(expected).hasSameElementsAs(solution1.letterCasePermutation("3z4"));
+        assertThat(expected).hasSameElementsAs(solution2.letterCasePermutation("3z4"));
+    }
+
+    @Test
+    public void test3() {
+        expected = Arrays.asList("12345");
+        assertThat(expected).hasSameElementsAs(solution1.letterCasePermutation("12345"));
+        assertThat(expected).hasSameElementsAs(solution2.letterCasePermutation("12345"));
+    }
 }