feat(7-kyu): kata/blowing-birthday-candles (#593)

docs/README.md

@@ -25,7 +25,7 @@ slug.
 
 | [1 kyu](/kata/1-kyu/index.md) | [2 kyu](/kata/2-kyu/index.md) | [3 kyu](/kata/3-kyu/index.md) | [4 kyu](/kata/4-kyu/index.md) | [5 kyu](/kata/5-kyu/index.md) | [6 kyu](/kata/6-kyu/index.md) | [7 kyu](/kata/7-kyu/index.md) | [8 kyu](/kata/8-kyu/index.md) | [beta](/kata/beta/index.md) | [retired](/kata/retired/index.md) |
 |:-----------------------------:|:-----------------------------:|:-----------------------------:|:-----------------------------:|:-----------------------------:|:-----------------------------:|:-----------------------------:|:-----------------------------:|:---------------------------:|:---------------------------------:|
-| 0 | 1 | 2 | 26 | 48 | 426 | 569 | 210 | 56 | 79 |
+| 0 | 1 | 2 | 26 | 48 | 426 | 570 | 210 | 56 | 79 |
 
 **Note:** The source code is written in Java 17 and may use language features that are incompatible
 with Java 8, 11.

kata/7-kyu/blowing-birthday-candles/README.md

@@ -0,0 +1,60 @@
+# [Blowing Birthday Candles](https://www.codewars.com/kata/blowing-birthday-candles "https://www.codewars.com/kata/6630da20f925eb3007c5a498")
+
+Today is the special day you've been waiting for — it's your birthday! It's 8 AM, and you're setting up your birthday
+cake for the party. It's time to put the candles on top.
+
+You take out all the candles you've bought. As you are about to put them on the cake, you just realize that there
+are numbers on each candle. What are these numbers?! After searching about it on the internet, turns out these are
+special candles. These candles need to be blown a certain number of times before they're finally extinguished, and those
+numbers on the candles are the required times to blow them.
+
+Being one who plans meticulously, you want to determine the total number of blows you need to extinguish all the candles
+once you've put them on the cake.
+
+## Task
+
+Given a string containing digits (representing the strength of the candles), calculate the number of blows you need to
+extinguish all the candles.
+
+Starting at the beginning of the string, each blow can only reach 3 candles, reducing
+their strength by one each. You can only reach more candles once those directly in front of you are extinguished.
+
+## Examples
+
+```
+Input: \"1321\"
+
+Move 1 | \"(132)1\" -> \"0211\"
+Move 2 | \"0(211)\" -> \"0100\"
+Move 3 | \"0(100)\" -> \"0000\"
+
+This should return 3.
+```
+
+```
+Input: \"0323456\"
+
+Move 1 | \"0(323)456\" -> \"0212456\"
+Move 2 | \"0(212)456\" -> \"0101456\"
+Move 3 | \"0(101)456\" -> \"0000456\"
+Move 4 | \"0000(456)\" -> \"0000345\"
+Move 5 | \"0000(345)\" -> \"0000234\"
+Move 6 | \"0000(234)\" -> \"0000123\"
+Move 7 | \"0000(123)\" -> \"0000012\"
+Move 8 | \"00000(12)\" -> \"0000001\"
+Move 9 | \"000000(1)\" -> \"0000000\"
+
+This should return 9.
+```
+
+```
+Input: \"2113\"
+
+Move 1 | \"(211)3\" -> \"1003\"
+Move 2 | \"(100)3\" -> \"0003\"
+Move 3 | \"000(3)\" -> \"0002\"
+Move 4 | \"000(2)\" -> \"0001\"
+Move 5 | \"000(1)\" -> \"0000\"
+
+This should return 5.
+```

kata/7-kyu/blowing-birthday-candles/main/Kata.java

@@ -0,0 +1,12 @@
+interface Kata {
+  static int blowCandles(String str) {
+    int[] blows = new int[4];
+    for (char c : str.toCharArray()) {
+      blows[0] = Math.max(c - 48 - blows[1] - blows[2], 0);
+      blows[2] = blows[1];
+      blows[1] = blows[0];
+      blows[3] += blows[0];
+    }
+    return blows[3];
+  }
+}

kata/7-kyu/blowing-birthday-candles/test/SolutionTest.java

@@ -0,0 +1,18 @@
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+
+class SolutionTest {
+  @ParameterizedTest
+  @CsvSource(textBlock = """
+      1321, 3
+      0323456, 9
+      2113, 5
+      1110, 1
+      121, 2
+      """)
+  void sample(String str, int expected) {
+    assertEquals(expected, Kata.blowCandles(str));
+  }
+}

kata/7-kyu/index.md

@@ -56,6 +56,7 @@
 - [Binary sXORe](binary-sxore)
 - [Bingo (Or Not)](bingo-or-not)
 - [Bits Battle](bits-battle)
+- [Blowing Birthday Candles](blowing-birthday-candles)
 - [Breaking chocolate problem](breaking-chocolate-problem)
 - [Broken sequence](broken-sequence)
 - [Bubblesort Once](bubblesort-once)