Add queen-attack exercise (#99)

config.json

@@ -218,6 +218,14 @@
         "prerequisites": [],
         "difficulty": 4
       },
+      {
+        "slug": "queen-attack",
+        "name": "Queen Attack",
+        "uuid": "90d79e15-c60c-4240-8cc1-cf969db2fb16",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 4
+      },
       {
         "slug": "rotational-cipher",
         "name": "Rotational Cipher",

exercises/practice/queen-attack/.docs/instructions.md

@@ -0,0 +1,21 @@
+# Instructions
+
+Given the position of two queens on a chess board, indicate whether or not they are positioned so that they can attack each other.
+
+In the game of chess, a queen can attack pieces which are on the same row, column, or diagonal.
+
+A chessboard can be represented by an 8 by 8 array.
+
+So if you are told the white queen is at `c5` (zero-indexed at column 2, row 3) and the black queen at `f2` (zero-indexed at column 5, row 6), then you know that the set-up is like so:
+
+![A chess board with two queens. Arrows emanating from the queen at c5 indicate possible directions of capture along file, rank and diagonal.](https://assets.exercism.org/images/exercises/queen-attack/queen-capture.svg)
+
+You are also able to answer whether the queens can attack each other.
+In this case, that answer would be yes, they can, because both pieces share a diagonal.
+
+## Credit
+
+The chessboard image was made by [habere-et-dispertire][habere-et-dispertire] using LaTeX and the [chessboard package][chessboard-package] by Ulrike Fischer.
+
+[habere-et-dispertire]: https://exercism.org/profiles/habere-et-dispertire
+[chessboard-package]: https://github.com/u-fischer/chessboard

exercises/practice/queen-attack/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "queen_attack.s"
+    ],
+    "test": [
+      "queen_attack_test.c"
+    ],
+    "example": [
+      ".meta/example.s"
+    ]
+  },
+  "blurb": "Given the position of two queens on a chess board, indicate whether or not they are positioned so that they can attack each other.",
+  "source": "J Dalbey's Programming Practice problems",
+  "source_url": "https://users.csc.calpoly.edu/~jdalbey/103/Projects/ProgrammingPractice.html"
+}

exercises/practice/queen-attack/.meta/example.s

@@ -0,0 +1,35 @@
+.text
+.globl can_create
+.globl can_attack
+
+/* extern int can_create(int row, int column); */
+can_create:
+        cmp     w0, #8
+        bhs     reject                  /* unsigned >= */
+
+        cmp     w1, #8
+        bhs     reject                  /* unsigned >= */
+
+accept:
+        mov     x0, #1
+        ret
+
+reject:
+        mov     x0, #0
+        ret
+
+/* extern int can_attack(int white_row, int white_column, int black_row, int black_column); */
+can_attack:
+        sub     x0, x0, x2
+        cbz     x0, accept
+
+        sub     x1, x1, x3
+        cbz     x1, accept
+
+        cmp     x0, x1
+        beq     accept
+
+        add     x0, x0, x1
+        cmp     x0, xzr
+        cset    x0, eq
+        ret

exercises/practice/queen-attack/.meta/tests.toml

@@ -0,0 +1,49 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[3ac4f735-d36c-44c4-a3e2-316f79704203]
+description = "Test creation of Queens with valid and invalid positions -> queen with a valid position"
+
+[4e812d5d-b974-4e38-9a6b-8e0492bfa7be]
+description = "Test creation of Queens with valid and invalid positions -> queen must have positive row"
+
+[f07b7536-b66b-4f08-beb9-4d70d891d5c8]
+description = "Test creation of Queens with valid and invalid positions -> queen must have row on board"
+
+[15a10794-36d9-4907-ae6b-e5a0d4c54ebe]
+description = "Test creation of Queens with valid and invalid positions -> queen must have positive column"
+
+[6907762d-0e8a-4c38-87fb-12f2f65f0ce4]
+description = "Test creation of Queens with valid and invalid positions -> queen must have column on board"
+
+[33ae4113-d237-42ee-bac1-e1e699c0c007]
+description = "Test the ability of one queen to attack another -> cannot attack"
+
+[eaa65540-ea7c-4152-8c21-003c7a68c914]
+description = "Test the ability of one queen to attack another -> can attack on same row"
+
+[bae6f609-2c0e-4154-af71-af82b7c31cea]
+description = "Test the ability of one queen to attack another -> can attack on same column"
+
+[0e1b4139-b90d-4562-bd58-dfa04f1746c7]
+description = "Test the ability of one queen to attack another -> can attack on first diagonal"
+
+[ff9b7ed4-e4b6-401b-8d16-bc894d6d3dcd]
+description = "Test the ability of one queen to attack another -> can attack on second diagonal"
+
+[0a71e605-6e28-4cc2-aa47-d20a2e71037a]
+description = "Test the ability of one queen to attack another -> can attack on third diagonal"
+
+[0790b588-ae73-4f1f-a968-dd0b34f45f86]
+description = "Test the ability of one queen to attack another -> can attack on fourth diagonal"
+
+[543f8fd4-2597-4aad-8d77-cbdab63619f8]
+description = "Test the ability of one queen to attack another -> cannot attack if falling diagonals are only the same when reflected across the longest falling diagonal"

exercises/practice/queen-attack/Makefile

@@ -0,0 +1,36 @@
+AS = aarch64-linux-gnu-as
+CC = aarch64-linux-gnu-gcc
+
+CFLAGS = -g -Wall -Wextra -pedantic -Werror
+LDFLAGS =
+
+ALL_LDFLAGS = -pie -Wl,--fatal-warnings
+
+ALL_CFLAGS = -std=c99 -fPIE $(CFLAGS)
+ALL_LDFLAGS += $(LDFLAGS)
+
+C_OBJS = $(patsubst %.c,%.o,$(wildcard *.c))
+AS_OBJS = $(patsubst %.s,%.o,$(wildcard *.s))
+ALL_OBJS = $(filter-out example.o,$(C_OBJS) $(AS_OBJS) vendor/unity.o)
+
+CC_CMD = $(CC) $(ALL_CFLAGS) -c -o $@ $<
+
+all: tests
+	qemu-aarch64 -L /usr/aarch64-linux-gnu ./$<
+
+tests: $(ALL_OBJS)
+	@$(CC) $(ALL_CFLAGS) $(ALL_LDFLAGS) -o $@ $(ALL_OBJS)
+
+%.o: %.s
+	@$(AS) -o $@ $<
+
+%.o: %.c
+	@$(CC_CMD)
+
+vendor/unity.o: vendor/unity.c vendor/unity.h vendor/unity_internals.h
+	@$(CC_CMD)
+
+clean:
+	@rm -f *.o vendor/*.o tests
+
+.PHONY: all clean

exercises/practice/queen-attack/queen_attack.s

@@ -0,0 +1,9 @@
+.text
+.globl can_create
+.globl can_attack
+
+can_create:
+    ret
+
+can_attack:
+    ret

exercises/practice/queen-attack/queen_attack_test.c

@@ -0,0 +1,95 @@
+#include "vendor/unity.h"
+
+// Returns 1 if queen can be created, otherwise 0.
+extern int can_create(int row, int column);
+
+// Returns 1 if queens attack, otherwise 0.
+extern int can_attack(int white_row, int white_column, int black_row, int black_column);
+
+void setUp(void) {
+}
+
+void tearDown(void) {
+}
+
+void test_queen_with_a_valid_position(void) {
+    TEST_ASSERT_TRUE(can_create(2, 2));
+}
+
+void test_queen_must_have_positive_row(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_FALSE(can_create(-2, 2));
+}
+
+void test_queen_must_have_row_on_board(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_FALSE(can_create(8, 4));
+}
+
+void test_queen_must_have_positive_column(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_FALSE(can_create(2, -2));
+}
+
+void test_queen_must_have_column_on_board(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_FALSE(can_create(4, 8));
+}
+
+void test_cannot_attack(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_FALSE(can_attack(2, 4, 6, 6));
+}
+
+void test_can_attack_on_same_row(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_TRUE(can_attack(2, 4, 2, 6));
+}
+
+void test_can_attack_on_same_column(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_TRUE(can_attack(4, 5, 2, 5));
+}
+
+void test_can_attack_on_first_diagonal(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_TRUE(can_attack(2, 2, 0, 4));
+}
+
+void test_can_attack_on_second_diagonal(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_TRUE(can_attack(2, 2, 3, 1));
+}
+
+void test_can_attack_on_third_diagonal(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_TRUE(can_attack(2, 2, 1, 1));
+}
+
+void test_can_attack_on_fourth_diagonal(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_TRUE(can_attack(1, 7, 0, 6));
+}
+
+void test_cannot_attack_if_falling_diagonals_are_only_the_same_when_reflected_across_the_longest_falling_diagonal(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_FALSE(can_attack(4, 1, 2, 5));
+}
+
+int main(void) {
+    UNITY_BEGIN();
+    RUN_TEST(test_queen_with_a_valid_position);
+    RUN_TEST(test_queen_must_have_positive_row);
+    RUN_TEST(test_queen_must_have_row_on_board);
+    RUN_TEST(test_queen_must_have_positive_column);
+    RUN_TEST(test_queen_must_have_column_on_board);
+    RUN_TEST(test_cannot_attack);
+    RUN_TEST(test_can_attack_on_same_row);
+    RUN_TEST(test_can_attack_on_same_column);
+    RUN_TEST(test_can_attack_on_first_diagonal);
+    RUN_TEST(test_can_attack_on_second_diagonal);
+    RUN_TEST(test_can_attack_on_third_diagonal);
+    RUN_TEST(test_can_attack_on_fourth_diagonal);
+    RUN_TEST(test_cannot_attack_if_falling_diagonals_are_only_the_same_when_reflected_across_the_longest_falling_diagonal);
+    return UNITY_END();
+}