feat: kata/playing-with-toy-blocks-can-you-build-a-4x4-square (#741)

* docs: kata description

* docs: sync progress

* feat: kata/playing-with-toy-blocks-can-you-build-a-4x4-square

---------

Co-authored-by: ParanoidUser <5120290+ParanoidUser@users.noreply.github.com>

Author: github-actions[bot]

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 | 443 | 605 | 228 | 56 | 82 |
+| 0 | 1 | 2 | 26 | 48 | 444 | 605 | 228 | 56 | 82 |
 
 **Note:** The source code is written in Java 17 and may use language features that are incompatible
 with Java 8, 11.

kata/6-kyu/index.md

@@ -282,6 +282,7 @@
 - [Playing on a chessboard](playing-on-a-chessboard)
 - [Playing with digits](playing-with-digits)
 - [Playing with passphrases](playing-with-passphrases)
+- [Playing With Toy Blocks ~ Can you build a 4x4 square?](playing-with-toy-blocks-can-you-build-a-4x4-square)
 - [+1 Array](plus-1-array)
 - [Points in the circle](points-in-the-circle)
 - [Polybius square cipher - encode](polybius-square-cipher-encode)

kata/6-kyu/playing-with-toy-blocks-can-you-build-a-4x4-square/README.md

@@ -0,0 +1,79 @@
+# [Playing With Toy Blocks ~ Can you build a 4x4 square?](https://www.codewars.com/kata/playing-with-toy-blocks-can-you-build-a-4x4-square "https://www.codewars.com/kata/5cab471da732b30018968071")
+
+## An Invitation
+
+Most of us played with toy blocks growing up. It was fun and you learned stuff. So what else can you do but rise to the challenge when a
+3-year-old exclaims, "Look, I made a square!", then pointing to a pile of blocks, "Can _you_ do it?"
+
+## Our Blocks
+
+Just to play along, of course we'll be viewing these blocks in two dimensions. Depth now being disregarded, it turns out the pile has four
+different sizes of block: `1x1`, `1x2`, `1x3`, and `1x4`. The smallest one represents the area of a square, the other three are rectangular,
+and all differ by their width. Integers matching these four widths are used to represent the blocks in the input.
+
+## The Square
+
+Well, the kid made a `4x4` square from this pile, so you'll have to match that. Noticing the way they fit together, you realize the
+structure must be built in fours rows, one row at a time, where the blocks must be placed horizontally. With the known types of block, there
+are five types of row you could build:
+
+1) 1 four-unit block
+2) 1 three-unit block plus 1 one-unit bock (in either order)
+3) 2 two-unit blocks
+4) 1 two-unit block plus 2 one-unit blocks (in any order)
+5) 4 one-unit blocks
+
+## Some Notes
+
+* Amounts for all four block sizes will each vary from `0` to `16`.
+* The total size of the pile will also vary from `0` to `16`.
+* A valid square doesn't have to use all given blocks.
+* The order of rows is irrelevant.
+
+## Some Examples
+
+Given `1, 3, 2, 2, 4, 1, 1, 3, 1, 4, 2` there are many ways you could construct a square. Here are three possibilities, as described by
+their four rows:
+
+ONE
+
+1. 1 four-unit block
+2. 2 two-unit blocks
+3. 1 four-unit block
+4. 4 one-unit blocks
+
+TWO
+
+1. 1 three-unit block plus 1 one-unit block
+2. 2 two-unit blocks
+3. 1 four-unit block
+4. 1 one-unit block plus 1 three-unit block
+
+THREE
+
+1. 2 two-unit blocks
+2. 1 three-unit block plus 1 one-unit block
+3. 1 four-unit block
+4. 2 one-unit blocks plus 1 two-unit block
+
+Given `1, 3, 2, 4, 3, 3, 2` there is no way to complete the task, as you could only build three rows of the correct length. The kid will not
+be impressed.
+
+NONE
+
+1. 1 four-unit block
+2. 2 two-unit blocks
+3. 1 three-unit block plus 1 one-unit block
+4. (here only sadness)
+
+## Input
+
+```
+blocks ~ array of random integers (1 <= x <= 4)
+```
+
+## Output
+
+```
+true or false ~ whether you can build a square
+```

kata/6-kyu/playing-with-toy-blocks-can-you-build-a-4x4-square/main/Kata.java

@@ -0,0 +1,9 @@
+interface Kata {
+  static boolean buildSquare(int[] blocks) {
+    int[] count = new int[4];
+    for (int b : blocks) {
+      count[b - 1]++;
+    }
+    return count[3] + Math.min(count[0], count[2]) + (Math.max(count[0] - count[2], 0) / 2 + count[1]) / 2 > 3;
+  }
+}

kata/6-kyu/playing-with-toy-blocks-can-you-build-a-4x4-square/test/KataTests.java

@@ -0,0 +1,15 @@
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+class KataTests {
+  @Test
+  void sample() {
+    assertTrue(Kata.buildSquare(new int[]{4, 3, 2, 1, 3, 1, 1, 2, 3, 1, 1}));
+    assertTrue(Kata.buildSquare(new int[]{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}));
+    assertFalse(Kata.buildSquare(new int[]{3, 1, 3, 1, 3, 1, 3, 2}));
+    assertFalse(Kata.buildSquare(new int[]{3, 2, 3, 3, 3, 3, 3, 3, 4, 2, 4}));
+    assertFalse(Kata.buildSquare(new int[]{1, 3, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1}));
+  }
+}