Add 2000. Reverse Prefix of Word

Author: manojbaishya

src/main/java/org/dojo/leetcode/Stacks.java

@@ -62,5 +62,12 @@ public boolean isValid(String s) {
 
     boolean isMatching(char self, char other) { return (self == '(' && other == ')') || (self == '{' && other == '}') || (self == '[' && other == ']'); }
 
-
+    public String reversePrefix(String word, char ch) {
+        for (int i = 0; i < word.length(); i++) {
+            if (word.charAt(i) == ch) {
+                return new StringBuilder(word.substring(0, i + 1)).reverse().append(word, i + 1, word.length()).toString();
+            }
+        }
+        return word;
+    }
 }

src/test/java/org/dojo/leetcode/StacksTests.java

@@ -1,6 +1,5 @@
 package org.dojo.leetcode;
 
-import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
@@ -9,6 +8,7 @@
 import java.util.stream.Stream;
 
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 class StacksTests {
     private final Stacks sut = new Stacks();
@@ -49,4 +49,20 @@ void isValid(String s, boolean expected) {
         System.out.printf("Expected: %s, Actual: %s\n", expected, actual);
         assert expected == actual;
     }
+
+    public static Stream<Arguments> reversePrefixData() {
+        return Stream.of(
+                Arguments.of("abcdefd", 'd', "dcbaefd"),
+                Arguments.of("xyxzxe", 'z', "zxyxxe"),
+                Arguments.of("abcd", 'z', "abcd")
+        );
+    }
+
+    @ParameterizedTest
+    @MethodSource("reversePrefixData")
+    void reversePrefix(String word, char ch, String expected) {
+        String actual = sut.reversePrefix(word, ch);
+        System.out.printf("Input: \"%s\", '%c' => Expected: \"%s\", Actual: \"%s\"\n", word, ch, expected, actual);
+        assertEquals(expected, actual);
+    }
 }