From b71c06afeff396b24d7142ddb8fc2b6e2993f651 Mon Sep 17 00:00:00 2001
From: Vitali Plagov <vplagov@pm.me>
Date: Wed, 24 Jan 2024 10:13:08 +0200
Subject: [PATCH] Problem 30

---
 .../problems/problems026to050/Problem030.java | 35 +++++++++++++++++++
 .../problems026to050/Problem030Test.java      | 13 +++++++
 2 files changed, 48 insertions(+)
 create mode 100644 src/main/java/net/projecteuler/problems/problems026to050/Problem030.java
 create mode 100644 src/test/java/net/projecteuler/problems/problems026to050/Problem030Test.java

diff --git a/src/main/java/net/projecteuler/problems/problems026to050/Problem030.java b/src/main/java/net/projecteuler/problems/problems026to050/Problem030.java
new file mode 100644
index 0000000..e10bff5
--- /dev/null
+++ b/src/main/java/net/projecteuler/problems/problems026to050/Problem030.java
@@ -0,0 +1,35 @@
+package net.projecteuler.problems.problems026to050;
+
+import java.util.stream.IntStream;
+
+public class Problem030 {
+
+  private static final int POWER = 5;
+
+  private static int sumOfFifthPowers(int number) {
+    return Integer.toString(number).chars()
+      .map(Character::getNumericValue)
+      .map(i -> (int) Math.pow(i, 5))
+      .sum();
+  }
+
+  private static int getBound(int power, int base) {
+    var number = power * (int) Math.pow(base, 5);
+    var maxLength = Integer.toString(number).length();
+
+    while (Integer.toString(number).length() <= maxLength) {
+      power++;
+      number = power * (int) Math.pow(base, 5);
+    }
+    return number;
+  }
+
+  public int solve() {
+    var start = getBound(POWER, 1);
+    var end = getBound(POWER, 9);
+
+    return IntStream.rangeClosed(start, end)
+      .filter(number -> number == sumOfFifthPowers(number))
+      .sum();
+  }
+}
diff --git a/src/test/java/net/projecteuler/problems/problems026to050/Problem030Test.java b/src/test/java/net/projecteuler/problems/problems026to050/Problem030Test.java
new file mode 100644
index 0000000..d0b7100
--- /dev/null
+++ b/src/test/java/net/projecteuler/problems/problems026to050/Problem030Test.java
@@ -0,0 +1,13 @@
+package net.projecteuler.problems.problems026to050;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class Problem030Test {
+
+  @Test
+  void solve() {
+    assertEquals(443839, new Problem030().solve());
+  }
+}