 artemkorsakov's solution

to Diamond in the Java Track

Published at Feb 05 2019 · 0 comments
Instructions
Test suite
Solution

The diamond kata takes as its input a letter, and outputs it in a diamond shape. Given a letter, it prints a diamond starting with 'A', with the supplied letter at the widest point.

Requirements

• The first row contains one 'A'.
• The last row contains one 'A'.
• All rows, except the first and last, have exactly two identical letters.
• All rows have as many trailing spaces as leading spaces. (This might be 0).
• The diamond is horizontally symmetric.
• The diamond is vertically symmetric.
• The diamond has a square shape (width equals height).
• The letters form a diamond shape.
• The top half has the letters in ascending order.
• The bottom half has the letters in descending order.
• The four corners (containing the spaces) are triangles.

Examples

In the following examples, spaces are indicated by · characters.

Diamond for letter 'A':

A

Diamond for letter 'C':

··A··
·B·B·
C···C
·B·B·
··A··

Diamond for letter 'E':

····A····
···B·B···
··C···C··
·D·····D·
E·······E
·D·····D·
··C···C··
···B·B···
····A····

Running the tests

You can run all the tests for an exercise by entering

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

DiamondPrinterTest.java

import org.junit.Ignore;
import org.junit.Before;
import org.junit.Test;

import java.util.List;

import static java.util.Arrays.asList;
import static java.util.Collections.singletonList;
import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertThat;

public class DiamondPrinterTest {

private DiamondPrinter diamondPrinter;

@Before
public void setUp() {
diamondPrinter = new DiamondPrinter();
}

@Test
public void testOneByOneDiamond() {
List<String> output = diamondPrinter.printToList('A');
assertThat(output, is(singletonList("A")));
}

@Ignore("Remove to run test")
@Test
public void testTwoByTwoDiamond() {
List<String> output = diamondPrinter.printToList('B');
assertThat(output, is(asList(" A ",
"B B",
" A ")));
}

@Ignore("Remove to run test")
@Test
public void testThreeByThreeDiamond() {
List<String> output = diamondPrinter.printToList('C');
assertThat(output, is(asList("  A  ",
" B B ",
"C   C",
" B B ",
"  A  ")));
}

@Ignore("Remove to run test")
@Test
public void testFourByFourDiamond() {
List<String> output = diamondPrinter.printToList('D');
assertThat(output, is(asList("   A   ",
"  B B  ",
" C   C ",
"D     D",
" C   C ",
"  B B  ",
"   A   ")));
}

@Ignore("Remove to run test")
@Test
public void testFullDiamond() {
List<String> output = diamondPrinter.printToList('Z');
assertThat(output, is(asList("                         A                         ",
"                        B B                        ",
"                       C   C                       ",
"                      D     D                      ",
"                     E       E                     ",
"                    F         F                    ",
"                   G           G                   ",
"                  H             H                  ",
"                 I               I                 ",
"                J                 J                ",
"               K                   K               ",
"              L                     L              ",
"             M                       M             ",
"            N                         N            ",
"           O                           O           ",
"          P                             P          ",
"         Q                               Q         ",
"        R                                 R        ",
"       S                                   S       ",
"      T                                     T      ",
"     U                                       U     ",
"    V                                         V    ",
"   W                                           W   ",
"  X                                             X  ",
" Y                                               Y ",
"Z                                                 Z",
" Y                                               Y ",
"  X                                             X  ",
"   W                                           W   ",
"    V                                         V    ",
"     U                                       U     ",
"      T                                     T      ",
"       S                                   S       ",
"        R                                 R        ",
"         Q                               Q         ",
"          P                             P          ",
"           O                           O           ",
"            N                         N            ",
"             M                       M             ",
"              L                     L              ",
"               K                   K               ",
"                J                 J                ",
"                 I               I                 ",
"                  H             H                  ",
"                   G           G                   ",
"                    F         F                    ",
"                     E       E                     ",
"                      D     D                      ",
"                       C   C                       ",
"                        B B                        ",
"                         A                         ")));
}

}
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

import static java.util.Collections.singletonList;

class DiamondPrinter {

List<String> printToList(char a) {
if (a == 'A') {
return singletonList("A");
}

int size = (a - 'A') * 2 + 1;
List<String> firstPart = new ArrayList<>();
for (int i = 'A'; i < a; i++) {
}
List<String> result = new ArrayList<>(firstPart);
Collections.reverse(firstPart);
return result;
}

private String getRow(char a, int size) {
int numberOfSpacesInside = (a == 'A') ? 0 : ((a - 'B') * 2 + 1);
int numberOfSpacesOut = (a == 'A') ? ((size - 1) / 2) : ((size - numberOfSpacesInside - 2) / 2);
char[] charsInside = new char[numberOfSpacesInside];
Arrays.fill(charsInside, ' ');
char[] charsOut = new char[numberOfSpacesOut];
Arrays.fill(charsOut, ' ');
String centre = (a == 'A') ? "A" : a + String.valueOf(charsInside) + a;
return String.valueOf(charsOut) + centre + String.valueOf(charsOut);
}

}