Add sum-of-multiples exercise

config.json

@@ -178,6 +178,14 @@
         "prerequisites": [],
         "difficulty": 3
       },
+      {
+        "slug": "sum-of-multiples",
+        "name": "Sum of Multiples",
+        "uuid": "d9228f0d-816b-46eb-8ca7-dbc8cd9f782d",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 3
+      },
       {
         "slug": "triangle",
         "name": "Triangle",

exercises/practice/diamond/diamond_test.c

@@ -2,7 +2,7 @@
 
 #define BUFFER_SIZE 3200
 
-void rows(char *buffer, char letter);
+extern void rows(char *buffer, char letter);
 
 void setUp(void) {
 }

exercises/practice/rectangles/rectangles_test.c

@@ -2,7 +2,7 @@
 
 #include <stddef.h>
 
-int rectangles(const char **strings);
+extern int rectangles(const char **strings);
 
 void setUp(void) {
 }

exercises/practice/sum-of-multiples/.docs/instructions.md

@@ -0,0 +1,27 @@
+# Instructions
+
+Your task is to write the code that calculates the energy points that get awarded to players when they complete a level.
+
+The points awarded depend on two things:
+
+- The level (a number) that the player completed.
+- The base value of each magical item collected by the player during that level.
+
+The energy points are awarded according to the following rules:
+
+1. For each magical item, take the base value and find all the multiples of that value that are less than the level number.
+2. Combine the sets of numbers.
+3. Remove any duplicates.
+4. Calculate the sum of all the numbers that are left.
+
+Let's look at an example:
+
+**The player completed level 20 and found two magical items with base values of 3 and 5.**
+
+To calculate the energy points earned by the player, we need to find all the unique multiples of these base values that are less than level 20.
+
+- Multiples of 3 less than 20: `{3, 6, 9, 12, 15, 18}`
+- Multiples of 5 less than 20: `{5, 10, 15}`
+- Combine the sets and remove duplicates: `{3, 5, 6, 9, 10, 12, 15, 18}`
+- Sum the unique multiples: `3 + 5 + 6 + 9 + 10 + 12 + 15 + 18 = 78`
+- Therefore, the player earns **78** energy points for completing level 20 and finding the two magical items with base values of 3 and 5.

exercises/practice/sum-of-multiples/.docs/introduction.md

@@ -0,0 +1,6 @@
+# Introduction
+
+You work for a company that makes an online, fantasy-survival game.
+
+When a player finishes a level, they are awarded energy points.
+The amount of energy awarded depends on which magical items the player found while exploring that level.

exercises/practice/sum-of-multiples/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "sum_of_multiples.s"
+    ],
+    "test": [
+      "sum_of_multiples_test.c"
+    ],
+    "example": [
+      ".meta/example.s"
+    ]
+  },
+  "blurb": "Given a number, find the sum of all the multiples of particular numbers up to but not including that number.",
+  "source": "A variation on Problem 1 at Project Euler",
+  "source_url": "https://projecteuler.net/problem=1"
+}

exercises/practice/sum-of-multiples/.meta/example.s

@@ -0,0 +1,31 @@
+.text
+.globl sum
+
+/* extern uint64_t sum(uint64_t limit, const uint64_t *factors, size_t factor_count); */
+sum:
+        lsl     x2, x2, #3              /* size of factors array, in bytes */
+        add     x2, x1, x2              /* end of factors array */
+        mov     x3, x0
+        mov     x0, xzr                 /* initialize total */
+        cbz     x3, .return
+
+.next_number:
+        sub     x3, x3, #1              /* number to check */
+        cbz     x3, .return
+
+        mov     x4, x1
+
+.next_factor:
+        cmp     x4, x2
+        beq     .next_number
+
+        ldr     x5, [x4], #8            /* load factor, post-increment */
+        udiv    x6, x3, x5              /* quotient */
+        msub    x7, x6, x5, x3          /* remainder */
+        cbnz    x7, .next_factor
+
+        add     x0, x0, x3              /* number x3 is a multiple of factor x5 */
+        b       .next_number
+
+.return:
+        ret

exercises/practice/sum-of-multiples/.meta/tests.toml

@@ -0,0 +1,58 @@
+# 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.
+
+[54aaab5a-ce86-4edc-8b40-d3ab2400a279]
+description = "no multiples within limit"
+
+[361e4e50-c89b-4f60-95ef-5bc5c595490a]
+description = "one factor has multiples within limit"
+
+[e644e070-040e-4ae0-9910-93c69fc3f7ce]
+description = "more than one multiple within limit"
+
+[607d6eb9-535c-41ce-91b5-3a61da3fa57f]
+description = "more than one factor with multiples within limit"
+
+[f47e8209-c0c5-4786-b07b-dc273bf86b9b]
+description = "each multiple is only counted once"
+
+[28c4b267-c980-4054-93e9-07723db615ac]
+description = "a much larger limit"
+
+[09c4494d-ff2d-4e0f-8421-f5532821ee12]
+description = "three factors"
+
+[2d0d5faa-f177-4ad6-bde9-ebb865083751]
+description = "factors not relatively prime"
+
+[ece8f2e8-96aa-4166-bbb7-6ce71261e354]
+description = "some pairs of factors relatively prime and some not"
+
+[624fdade-6ffb-400e-8472-456a38c171c0]
+description = "one factor is a multiple of another"
+
+[949ee7eb-db51-479c-b5cb-4a22b40ac057]
+description = "much larger factors"
+
+[41093673-acbd-482c-ab80-d00a0cbedecd]
+description = "all numbers are multiples of 1"
+
+[1730453b-baaa-438e-a9c2-d754497b2a76]
+description = "no factors means an empty sum"
+
+[214a01e9-f4bf-45bb-80f1-1dce9fbb0310]
+description = "the only multiple of 0 is 0"
+
+[c423ae21-a0cb-4ec7-aeb1-32971af5b510]
+description = "the factor 0 does not affect the sum of multiples of other factors"
+
+[17053ba9-112f-4ac0-aadb-0519dd836342]
+description = "solutions using include-exclude must extend to cardinality greater than 3"

exercises/practice/sum-of-multiples/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/sum-of-multiples/sum_of_multiples.s

@@ -0,0 +1,5 @@
+.text
+.globl sum
+
+sum:
+    ret

exercises/practice/sum-of-multiples/sum_of_multiples_test.c

@@ -0,0 +1,129 @@
+#include "vendor/unity.h"
+
+#include <stddef.h>
+#include <stdint.h>
+
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+
+extern uint64_t sum(uint64_t limit, const uint64_t *factors, size_t factor_count);
+
+void setUp(void) {
+}
+
+void tearDown(void) {
+}
+
+void test_no_multiples_within_limit(void) {
+    const uint64_t factors[] = {3, 5};
+    TEST_ASSERT_EQUAL_UINT64(0, sum(1, factors, ARRAY_SIZE(factors)));
+}
+
+void test_one_factor_has_multiples_within_limit(void) {
+    TEST_IGNORE();
+    const uint64_t factors[] = {3, 5};
+    TEST_ASSERT_EQUAL_UINT64(3, sum(4, factors, ARRAY_SIZE(factors)));
+}
+
+void test_more_than_one_multiple_within_limit(void) {
+    TEST_IGNORE();
+    const uint64_t factors[] = {3};
+    TEST_ASSERT_EQUAL_UINT64(9, sum(7, factors, ARRAY_SIZE(factors)));
+}
+
+void test_more_than_one_factor_with_multiples_within_limit(void) {
+    TEST_IGNORE();
+    const uint64_t factors[] = {3, 5};
+    TEST_ASSERT_EQUAL_UINT64(23, sum(10, factors, ARRAY_SIZE(factors)));
+}
+
+void test_each_multiple_is_only_counted_once(void) {
+    TEST_IGNORE();
+    const uint64_t factors[] = {3, 5};
+    TEST_ASSERT_EQUAL_UINT64(2318, sum(100, factors, ARRAY_SIZE(factors)));
+}
+
+void test_a_much_larger_limit(void) {
+    TEST_IGNORE();
+    const uint64_t factors[] = {3, 5};
+    TEST_ASSERT_EQUAL_UINT64(233168, sum(1000, factors, ARRAY_SIZE(factors)));
+}
+
+void test_three_factors(void) {
+    TEST_IGNORE();
+    const uint64_t factors[] = {7, 13, 17};
+    TEST_ASSERT_EQUAL_UINT64(51, sum(20, factors, ARRAY_SIZE(factors)));
+}
+
+void test_factors_not_relatively_prime(void) {
+    TEST_IGNORE();
+    const uint64_t factors[] = {4, 6};
+    TEST_ASSERT_EQUAL_UINT64(30, sum(15, factors, ARRAY_SIZE(factors)));
+}
+
+void test_some_pairs_of_factors_relatively_prime_and_some_not(void) {
+    TEST_IGNORE();
+    const uint64_t factors[] = {5, 6, 8};
+    TEST_ASSERT_EQUAL_UINT64(4419, sum(150, factors, ARRAY_SIZE(factors)));
+}
+
+void test_one_factor_is_a_multiple_of_another(void) {
+    TEST_IGNORE();
+    const uint64_t factors[] = {5, 25};
+    TEST_ASSERT_EQUAL_UINT64(275, sum(51, factors, ARRAY_SIZE(factors)));
+}
+
+void test_much_larger_factors(void) {
+    TEST_IGNORE();
+    const uint64_t factors[] = {43, 47};
+    TEST_ASSERT_EQUAL_UINT64(2203160, sum(10000, factors, ARRAY_SIZE(factors)));
+}
+
+void test_all_numbers_are_multiples_of_1(void) {
+    TEST_IGNORE();
+    const uint64_t factors[] = {1};
+    TEST_ASSERT_EQUAL_UINT64(4950, sum(100, factors, ARRAY_SIZE(factors)));
+}
+
+void test_no_factors_means_an_empty_sum(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_EQUAL_UINT64(0, sum(10000, NULL, 0));
+}
+
+void test_the_only_multiple_of_0_is_0(void) {
+    TEST_IGNORE();
+    const uint64_t factors[] = {0};
+    TEST_ASSERT_EQUAL_UINT64(0, sum(1, factors, ARRAY_SIZE(factors)));
+}
+
+void test_the_factor_0_does_not_affect_the_sum_of_multiples_of_other_factors(void) {
+    TEST_IGNORE();
+    const uint64_t factors[] = {3, 0};
+    TEST_ASSERT_EQUAL_UINT64(3, sum(4, factors, ARRAY_SIZE(factors)));
+}
+
+void test_solutions_using_includeexclude_must_extend_to_cardinality_greater_than_3(void) {
+    TEST_IGNORE();
+    const uint64_t factors[] = {2, 3, 5, 7, 11};
+    TEST_ASSERT_EQUAL_UINT64(39614537, sum(10000, factors, ARRAY_SIZE(factors)));
+}
+
+int main(void) {
+    UNITY_BEGIN();
+    RUN_TEST(test_no_multiples_within_limit);
+    RUN_TEST(test_one_factor_has_multiples_within_limit);
+    RUN_TEST(test_more_than_one_multiple_within_limit);
+    RUN_TEST(test_more_than_one_factor_with_multiples_within_limit);
+    RUN_TEST(test_each_multiple_is_only_counted_once);
+    RUN_TEST(test_a_much_larger_limit);
+    RUN_TEST(test_three_factors);
+    RUN_TEST(test_factors_not_relatively_prime);
+    RUN_TEST(test_some_pairs_of_factors_relatively_prime_and_some_not);
+    RUN_TEST(test_one_factor_is_a_multiple_of_another);
+    RUN_TEST(test_much_larger_factors);
+    RUN_TEST(test_all_numbers_are_multiples_of_1);
+    RUN_TEST(test_no_factors_means_an_empty_sum);
+    RUN_TEST(test_the_only_multiple_of_0_is_0);
+    RUN_TEST(test_the_factor_0_does_not_affect_the_sum_of_multiples_of_other_factors);
+    RUN_TEST(test_solutions_using_includeexclude_must_extend_to_cardinality_greater_than_3);
+    return UNITY_END();
+}