Add id0001

.editorconfig

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+[*]
+cpp_indent_braces=false
+cpp_indent_multi_line_relative_to=innermost_parenthesis
+cpp_indent_within_parentheses=indent
+cpp_indent_preserve_within_parentheses=false
+cpp_indent_case_labels=true
+cpp_indent_case_contents=true
+cpp_indent_case_contents_when_block=false
+cpp_indent_lambda_braces_when_parameter=true
+cpp_indent_goto_labels=one_left
+cpp_indent_preprocessor=leftmost_column
+cpp_indent_access_specifiers=false
+cpp_indent_namespace_contents=true
+cpp_indent_preserve_comments=false
+cpp_new_line_before_open_brace_namespace=ignore
+cpp_new_line_before_open_brace_type=ignore
+cpp_new_line_before_open_brace_function=ignore
+cpp_new_line_before_open_brace_block=ignore
+cpp_new_line_before_open_brace_lambda=ignore
+cpp_new_line_scope_braces_on_separate_lines=false
+cpp_new_line_close_brace_same_line_empty_type=false
+cpp_new_line_close_brace_same_line_empty_function=true
+cpp_new_line_before_catch=true
+cpp_new_line_before_else=true
+cpp_new_line_before_while_in_do_while=true
+cpp_space_before_function_open_parenthesis=remove
+cpp_space_within_parameter_list_parentheses=false
+cpp_space_between_empty_parameter_list_parentheses=false
+cpp_space_after_keywords_in_control_flow_statements=true
+cpp_space_within_control_flow_statement_parentheses=false
+cpp_space_before_lambda_open_parenthesis=false
+cpp_space_within_cast_parentheses=false
+cpp_space_after_cast_close_parenthesis=false
+cpp_space_within_expression_parentheses=false
+cpp_space_before_block_open_brace=true
+cpp_space_between_empty_braces=false
+cpp_space_before_initializer_list_open_brace=true
+cpp_space_within_initializer_list_braces=true
+cpp_space_preserve_in_initializer_list=true
+cpp_space_before_open_square_bracket=false
+cpp_space_within_square_brackets=false
+cpp_space_before_empty_square_brackets=false
+cpp_space_between_empty_square_brackets=false
+cpp_space_group_square_brackets=true
+cpp_space_within_lambda_brackets=false
+cpp_space_between_empty_lambda_brackets=false
+cpp_space_before_comma=false
+cpp_space_after_comma=true
+cpp_space_remove_around_member_operators=true
+cpp_space_before_inheritance_colon=true
+cpp_space_before_constructor_colon=true
+cpp_space_remove_before_semicolon=true
+cpp_space_after_semicolon=false
+cpp_space_remove_around_unary_operator=true
+cpp_space_around_binary_operator=insert
+cpp_space_around_assignment_operator=insert
+cpp_space_pointer_reference_alignment=left
+cpp_space_around_ternary_operator=insert
+cpp_wrap_preserve_blocks=one_liners

.gitignore

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+a.out
+*.exe
+*.o
+.vscode/

Makefile

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+CC = gcc
+CFLAGS = -O3 -pedantic -std=c99 -Wall -Wextra
+LIBM = -lm
+TWOS_COMPLEMENT = -fno-strict-overflow -fwrapv
+
+all: \
+	id0001
+
+euler: src/euler.h src/euler.c
+	$(CC) $(CFLAGS) -c src/euler.c -o $@.o 
+
+id0001: src/id0001.c euler
+	$(CC) $(CFLAGS) $< -o $@.o euler.o
+
+clean:
+	rm -rf *.o

cstyle.md

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+# C language style guide
+
+## Indentation
+
+- Use spaces instead of tabs.
+- The indentation size is four spaces.
+- Indent `case` labels.
+- Do not put multiple statements on a single line.
+- Do not put multiple assignments on a single line.
+- Do not leave whitespace at the end of lines.
+
+## Wrapping
+
+- The line limit is 80 characters.
+- Split long strings to meet the character limit.
+
+## Bracing
+
+- Every brace (`{`) or brace-semicolon pair (`};`) should have its own line,
+  except during empty initialization or during array initialization when all array
+  items are placed on a single line.
+- Always use braces with control structures, even when optional.
+- Separate functions and control structures by exactly one blank line.
+
+## Spacing
+
+Defer to the Linux Kernel Coding Style
+[Section 3.1: Spacing](https://www.kernel.org/doc/html/v4.10/process/coding-style.html)
+for spacing considerations.
+
+## Naming
+
+- Use `UPPER_SNAKE_CASE` for global constants, constant macros, and enumeration
+  members.
+- Use `PascalCase` for struct names, enumeration names, and type definitions.
+- Use `lower_snake_case` for global functions.
+- Use `lowercase` for static functions.
+- Use `camelCase` for local variables, struct fields, and function arguments.
+
+Always use descriptive names. Abbreviated names are forbidden except in the
+following approved use cases. If a value is arbitrary, use the corresponding
+abbreviation based on its type. If several values are abitrary, begin with the
+corresponding type-based abbreviation and continue alphabetically. If doing so
+is impractical, use numeric suffixes instead.
+
+| Letter | Appropriate use                                                                              |
+| :----: | :------------------------------------------------------------------------------------------- |
+|  `a`   | arbitrary object, area                                                                       |
+|  `b`   | blue color component, boundary points in Pick\'s Theorem                                     |
+|  `e`   | arbitrary edge                                                                               |
+|  `dx`  | change in an arbitrary dimension                                                             |
+|  `g`   | green color component, arbitrary graph                                                       |
+|  `hi`  | larger pointer, point above, upper buffer                                                    |
+|  `i`   | abitrary counter, matrix index in an arbitrary dimension, interior points in Pick\'s Theorem |
+|  `k`   | term number, arbitrary constant                                                              |
+|  `l`   | arbitrary line                                                                               |
+|  `lo`  | smaller pointer, point below, lower buffer                                                   |
+|  `m`   | matrix size in an arbitrary dimension                                                        |
+| `max`  | inclusive maximum, exclusive interval upper bound                                            |
+| `mid`  | middle pointer, middle buffer                                                                |
+| `min`  | inclusive minimum, inclusive interval lower bound                                            |
+|  `n`   | count, arbitrary integer                                                                     |
+|  `p`   | arbitrary pointer, arbitrary point                                                           |
+|  `q`   | arbitrary rational number                                                                    |
+|  `r`   | red color component, arbitrary real number                                                   |
+|  `u`   | arbitrary vertex                                                                             |
+|  `x`   | vector in an arbitrary dimension, position in an arbitrary dimension                         |
+
+## Type definitions
+
+- Always use type definitions for enumeration types.
+- Always use type definitions to obscure pointers to structs.
+
+### Macros
+
+- Only use macros to define constants.
+- When multiple related integer constants are defined, use an enumeration
+  instead.

src/euler.c

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+// Licensed under the MIT License.
+
+// Multiples of 3 or 5
+
+#include <stdio.h>
+#include "euler.h"
+
+void euler_submit(int id, clock_t start)
+{
+    printf("%04d %lf\n", 
+        id, 
+        (double)(clock() - start) / CLOCKS_PER_SEC);
+}

src/euler.h

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+#include <time.h>
+
+void euler_submit(int id, clock_t start);

src/id0001.c

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+#include "euler.h"
+
+int math_gaussian_sum(int n)
+{
+    return n * (n + 1) / 2;
+}
+
+int main(void)
+{
+    clock_t start = clock();
+    int sum = (3 * math_gaussian_sum(999 / 3)) +
+        (5 * math_gaussian_sum(999 / 5)) -
+        (15 * math_gaussian_sum(999 / 15));
+
+    euler_submit(sum, start);
+
+    return 0;
+}

tools/test.sh

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+for i in {0001..0001};
+do
+    ./../id${i}.o
+done