sir-gon · sir-gon · Jul 9, 2025 · Jul 9, 2025
diff --git a/...ava/src/main/java/ae/hackerrank/interview_preparation_kit/miscellaneous/FlippingBits.java b/...ava/src/main/java/ae/hackerrank/interview_preparation_kit/miscellaneous/FlippingBits.java
@@ -0,0 +1,34 @@
+package ae.hackerrank.interview_preparation_kit.miscellaneous;
+
+/**
+ * AngryFlorist.
+ *
+ * @link Problem definition
+ *       [[docs/hackerrank/interview_preparation_kit/miscellaneous/flipping-bits.md]]
+ */
+public class FlippingBits {
+
+  private FlippingBits() {}
+
+  /**
+   * flippingBits.
+   */
+  public static long flippingBits(long n) {
+    String binaryString = Long.toBinaryString(n);
+    binaryString = String.format("%32s", binaryString); // Ensure 32 bits
+
+    StringBuilder resultBinaryString = new StringBuilder();
+
+    for (int i = 0; i < binaryString.length(); i++) {
+      char binDigit = binaryString.charAt(i);
+
+      if (binDigit == '1') {
+        resultBinaryString.append('0');
+      } else {
+        resultBinaryString.append('1');
+      }
+    }
+
+    return Long.parseLong(resultBinaryString.toString(), 2);
+  }
+}
diff --git a/...src/test/java/ae/hackerrank/interview_preparation_kit/miscellaneous/FlippingBitsTest.java b/...src/test/java/ae/hackerrank/interview_preparation_kit/miscellaneous/FlippingBitsTest.java
@@ -0,0 +1,61 @@
+package ae.hackerrank.interview_preparation_kit.miscellaneous;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.IOException;
+import java.util.List;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.TestInstance;
+import org.junit.jupiter.api.TestInstance.Lifecycle;
+import util.JsonLoader;
+
+/**
+ * FlippingBitsTflippingBits.
+ */
+@TestInstance(Lifecycle.PER_CLASS)
+class FlippingBitsTest {
+  /**
+   * FlippingBitsTestCaseTest.
+   */
+  public static class FlippingBitsTestCaseTest {
+    public long input;
+    public long answer;
+  }
+
+  /**
+   * FlippingBitsTestCase.
+   */
+  public static class FlippingBitsTestCase {
+    public String title;
+    public List<FlippingBitsTestCaseTest> tests;
+  }
+
+  private List<FlippingBitsTestCase> testCases;
+
+  @BeforeAll
+  void setup() throws IOException {
+    String path = String.join("/",
+        "hackerrank",
+        "interview_preparation_kit",
+        "miscellaneous",
+        "flipping_bits.testcases.json");
+
+    this.testCases = JsonLoader.loadJson(path, FlippingBitsTestCase.class);
+  }
+
+  @Test
+  void testLuckBalance() {
+    for (FlippingBitsTestCase tests : testCases) {
+      for (FlippingBitsTestCaseTest test : tests.tests) {
+        Long result = FlippingBits.flippingBits(test.input);
+
+        assertEquals(test.answer, result,
+            "%s(%s) => must be: %d".formatted(
+              "FlippingBits.flippingBits",
+              test.input,
+              test.answer));
+      }
+    }
+  }
+}
diff --git a/...resources/hackerrank/interview_preparation_kit/miscellaneous/flipping_bits.testcases.json b/...resources/hackerrank/interview_preparation_kit/miscellaneous/flipping_bits.testcases.json
@@ -0,0 +1,49 @@
+[
+  {
+    "title": "Sample Test Case 0",
+    "tests": [
+      {
+        "input": 2147483647,
+        "answer": 2147483648
+      },
+      {
+        "input": 1,
+        "answer": 4294967294
+      },
+      {
+        "input": 0,
+        "answer": 4294967295
+      }
+    ]
+  },
+  {
+    "title": "Sample Test Case 1",
+    "tests": [
+      {
+        "input": 4,
+        "answer": 4294967291
+      },
+      {
+        "input": 123456,
+        "answer": 4294843839
+      }
+    ]
+  },
+  {
+    "title": "Sample Test Case 2",
+    "tests": [
+      {
+        "input": 0,
+        "answer": 4294967295
+      },
+      {
+        "input": 802743475,
+        "answer": 3492223820
+      },
+      {
+        "input": 35601423,
+        "answer": 4259365872
+      }
+    ]
+  }
+]
diff --git a/docs/hackerrank/interview_preparation_kit/miscellaneous/flipping-bits.md b/docs/hackerrank/interview_preparation_kit/miscellaneous/flipping-bits.md
@@ -0,0 +1,120 @@
+# [Miscellaneous: Flipping bits](https://www.hackerrank.com/challenges/flipping-bits)
+
+- Difficulty:  `#easy`
+- Category: `#ProblemSolvingBasic` `#BitManipulation`
+
+You will be given a list of 32 bit unsigned integers.
+Flip all the bits ( `1 -> 0` and `0 -> 1`)
+and return the result as an unsigned integer.
+
+## Example
+
+$ n = 9_{10} $. We're working with 32 bits, so:
+
+$ 9_{10} = 1001_{2} $
+
+$ 00000000000000000000000000001001_{2} = 9_{10} $
+$ 11111111111111111111111111110110_{2} = 4294967286_{10} $
+
+Return `4294967286`
+
+## Function Description
+
+Complete the flippingBits function in the editor below.
+
+flippingBits has the following parameter(s):
+
+- `int n`: an integer
+
+## Returns
+
+- `int`: the unsigned decimal integer result
+
+## Input Format
+
+The first line of the input contains `q`, the number of queries.
+Each of the next `q` lines contain an integer, `n`, to process.
+
+## Constraints
+
+- $ 1 \leq q \leq 100 $
+- $ 0 \leq n \leq 2^{32} $
+
+## Sample Input 0
+
+```text
+3
+2147483647
+1
+0
+```
+
+## Sample Output 0
+
+```text
+2147483648
+4294967294
+4294967295
+```
+
+## Explanation 0
+
+$ 01111111111111111111111111111111_{2} = 2147483647_{10} $
+$ 10000000000000000000000000000000_{2} = 2147483648_{10} $
+
+$ 00000000000000000000000000000001_{2} = 1_{10} $
+$ 11111111111111111111111111111110_{2} = 4294967294_{10} $
+
+$ 00000000000000000000000000000000_{2} = 0_{10} $
+$ 11111111111111111111111111111110_{2} = 4294967295_{10} $
+
+## Sample Input 1
+
+```text
+2
+4
+123456
+```
+
+## Sample Output 1
+
+```text
+4294967291
+4294843839
+```
+
+## Explanation 1
+
+$ 00000000000000000000000000000100_{2} = 4_{10} $
+$ 11111111111111111111111111111011_{2} = 4294967291_{10} $
+
+$ 00000000000000011110001001000000_{2} = 4_{10} $
+$ 11111111111111100001110110111111_{2} = 429484389_{10} $
+
+## Sample Input 2
+
+```text
+3
+0
+802743475
+35601423
+```
+
+## Sample Output 2
+
+```text
+4294967295
+3492223820
+4259365872
+```
+
+## Explanation 2
+
+$ 00000000000000000000000000000000_{2} = 4_{10} $
+$ 11111111111111111111111111111111_{2} = 4294967295_{10} $
+
+$ 00101111110110001110010010110011_{2} = 802743475_{10} $
+$ 11010000001001110001101101001100_{2} = 3492223820_{10} $
+
+$ 00000010000111110011110000001111_{2} = 35601423_{10} $
+$ 11111101111000001100001111110000_{2} = 4259365872_{10} $