solve p22 in c++

README.rst

@@ -50,7 +50,7 @@ Olivia's Project Euler Solutions
 |            | |gcc|, |pcc|, |tcc| |br| |        | |C-Cov| |br|      |
 |            | C11+ in: |msvc| [1]_     |        | |CodeQL|          |
 +------------+--------------------------+--------+-------------------+
-| C++        | C++98+ in: |br| |clang|  | 13     | |Cpi| |br|        |
+| C++        | C++98+ in: |br| |clang|  | 14     | |Cpi| |br|        |
 |            | |gcc| |br|               |        | |Cp-Cov| |br|     |
 |            | C++14+ in: |msvc| [1]_   |        | |CodeQL|          |
 +------------+--------------------------+--------+-------------------+

cplusplus/README.rst

@@ -174,6 +174,7 @@ Problems Solved
 -  ☒ `14 <./src/p0014.cpp>`__
 -  ☒ `15 <./src/p0015.cpp>`__
 -  ☒ `17 <./src/p0017.cpp>`__
+-  ☒ `22 <./src/p0022.cpp>`__
 -  ☒ `34 <./src/p0034.cpp>`__
 -  ☒ `76 <./src/p0076.cpp>`__
 -  ☒ `836 <./src/p0836.cpp>`__

cplusplus/src/include/utils.h

@@ -0,0 +1,102 @@
+#pragma once
+#include <stdlib.h>
+#include <string.h>
+#ifdef _WIN32
+#include <direct.h>
+#include <windows.h>
+#define PATH_SEPARATOR "\\"
+#else
+#include <libgen.h>
+#include <unistd.h>
+#define PATH_SEPARATOR "/"
+#endif
+
+char* get_parent_directory(char* path, const unsigned int levels) {
+#ifdef _WIN32
+    static char drive[_MAX_DRIVE];
+    static char dir[_MAX_DIR];
+    _splitpath(path, drive, dir, NULL, NULL);
+    for (unsigned int i = 0; i < levels; ++i) {
+        size_t len = strlen(dir);
+        if (len > 1 && (dir[len - 1] == '\\' || dir[len - 1] == '/')) {
+            dir[len - 1] = '\0';
+        }
+        char* last_slash = strrchr(dir, '\\');
+        if (!last_slash) last_slash = strrchr(dir, '/');
+        if (last_slash) *last_slash = '\0';
+    }
+    static char parent_dir[_MAX_PATH];
+    snprintf(parent_dir, sizeof(parent_dir), "%s%s", drive, dir);
+    return parent_dir;
+#else
+    char* dir = dirname(path);
+    for (unsigned int i = 0; i < levels; ++i) {
+        dir = dirname(dir);
+        if (strcmp(dir, "/") == 0 || strcmp(dir, ".") == 0) {
+            break;
+        }
+    }
+    return dir;
+#endif
+}
+
+std::string get_data_file(const char *name) {
+    const char* start = __FILE__;
+#ifdef _WIN32
+    char absolute_path[MAX_PATH];
+    if (!_fullpath(absolute_path, start, MAX_PATH)) {
+        perror("_fullpath");
+        return NULL;
+    }
+#else
+   char* absolute_path = realpath(start, NULL);
+    if (!absolute_path) {
+        perror("realpath");
+        return NULL;
+    }
+#endif
+    char* parents_dir = get_parent_directory(absolute_path, 3);
+    const size_t p_len = strlen(parents_dir),
+    name_len = strlen(name);
+    char *file_path = (char *)malloc(p_len + name_len + 8);
+    memcpy(file_path, parents_dir, p_len);
+    memcpy(file_path + p_len, PATH_SEPARATOR "_data" PATH_SEPARATOR, 7);
+    memcpy(file_path + p_len + 7, name, name_len);
+    file_path[p_len + name_len + 7] = 0;
+    FILE* file = fopen(file_path, "r");
+#ifndef _WIN32
+    free(absolute_path);
+#endif
+//    free(parents_dir);
+    free(file_path);
+    if (!file) {
+        perror("fopen");
+        return NULL;
+    }
+
+    fseek(file, 0, SEEK_END);
+    size_t length = ftell(file);
+    fseek(file, 0, SEEK_SET);
+
+    char* buffer = (char*)malloc(length + 1);
+    if (!buffer) {
+        perror("malloc");
+        fclose(file);
+        return NULL;
+    }
+
+    const size_t ret_code = fread(buffer, 1, length, file);
+    if (ret_code != length) {
+        if (feof(file))
+            printf("Error reading %s: unexpected end of file, read %llu of %llu bytes expected\n", name, (unsigned long long)ret_code, (unsigned long long)length);
+        else if (ferror(file))
+            perror("Error reading data file");
+    }
+
+    buffer[length] = 0;
+    fclose(file);
+
+    std::string ret(buffer);
+    free(buffer);
+    return ret;
+}

cplusplus/src/p0022.cpp

@@ -0,0 +1,53 @@
+/**
+ * Project Euler Problem 22
+ * 
+ * I know that this could be done faster with a traditional for loop, but I wanted
+ * to see if iterators were reasonably possible in C, since it makes the prime
+ * number infrastructure a lot easier to set up.
+ * 
+ * Problem:
+ * 
+ * If we list all the natural numbers below 10 that are multiples of 3 or 5, we
+ * get 3, 5, 6 and 9. The sum of these multiples is 23.
+ * 
+ * Find the sum of all the multiples of 3 or 5 below 1000.
+ */
+#ifndef EULER_P0022
+#define EULER_P0022
+#include <iostream>
+#include <vector>
+#include <algorithm>
+#include "include/utils.h"
+
+unsigned long long p0022() {
+    unsigned long long answer = 0;
+    std::string fstring = get_data_file("p0022_names.txt");
+    const unsigned int name_count = 5163;
+    std::vector<std::string> names(5163, "");
+    size_t idx = 0, i = 0, pi = 0;
+    do {
+        while (fstring[i] && fstring[i] != ',')
+            i++;
+        const size_t len = i - pi - 2;
+        names[idx] = fstring.substr(pi + 1, len);
+        idx++;
+        pi = ++i;
+    } while (fstring[i]);
+    std::sort(names.begin(), names.end());
+    for (idx = 0; idx < name_count; idx++) {
+        unsigned long score = 0;
+        for (i = 0; names[idx][i]; i++) {
+            score += names[idx][i] & 0x3F;
+        }
+        answer += score * (idx + 1);
+    }
+    return answer;
+}
+
+#ifndef UNITY_END
+int main(int argc, char const *argv[])  {
+    std::cout << p0022() << std::endl;
+    return 0;
+}
+#endif
+#endif

cplusplus/test.cpp

@@ -17,6 +17,7 @@
 #include "src/p0015.cpp"
 // #include "src/p0016.cpp"
 #include "src/p0017.cpp"
+#include "src/p0022.cpp"
 #include "src/p0034.cpp"
 #include "src/p0076.cpp"
 #include "src/p0836.cpp"
@@ -45,6 +46,7 @@ static const Answer answers[] = {
 	{15,	137846528820,	p0015},
 	// {16,	1366,			p0016},
 	{17,	21124,			p0017},
+	{22,	871198282,			p0022},
 	{34,	40730,			p0034},
 	{76,	190569291,		(unsigned long long (*)()) p0076},
 };

cplusplus/test_euler.py

@@ -30,6 +30,7 @@
     14: 837799,
     15: 137846528820,
     17: 21124,
+    22: 871198282,
     34: 40730,
     76: 190569291,
     836: b"aprilfoolsjoke",

docs/cplusplus/p0015.rst

@@ -1,24 +1,24 @@
-C++ Implementation of Problem 15
+C++ Implementation of Problem 22
 ================================
 
-View source code :source:`cplusplus/src/p0015.cpp`
+View source code :source:`cplusplus/src/p0022.cpp`
 
 Includes
 --------
 
-- `math.h <./math.html>`__
+- `utils.h <./utils.html>`__
 
 Solution
 --------
 
-.. cpp:function:: unsigned long long p0015()
+.. cpp:function:: unsigned long long p0022()
 
 .. cpp:function:: int main(int argc, char const *argv[])
 
    .. note:: 
 
       This function is only present in the Python test runner, or when compiling as a standalone program.
 
-.. literalinclude:: ../../cplusplus/src/p0015.cpp
+.. literalinclude:: ../../cplusplus/src/p0022.cpp
    :language: C++
    :linenos:

docs/cplusplus/utils.rst

@@ -0,0 +1,18 @@
+utils.h
+=======
+
+View source code :source:`cplusplus/src/include/utils.h`
+
+.. cpp:namespace-push:: utils
+    
+.. cpp:function:: std::string get_data_file(const char *name)
+
+    Return a character array containing the whole contents of a file found in _data.
+
+.. cpp:function:: char *get_parent_directory(const char *name, const unsigned int levels)
+
+.. cpp:namespace-pop::
+
+.. literalinclude:: ../../cplusplus/src/include/utils.h
+   :language: C++
+   :linenos:

docs/index.rst

@@ -169,7 +169,7 @@ Problems Solved
 +-----------+------------+------------+------------+------------+------------+------------+
 |:prob:`21` |            |            |            |            |:py-d:`0021`|            |
 +-----------+------------+------------+------------+------------+------------+------------+
-|:prob:`22` |:c-d:`0022` |            |:cs-d:`0022`|:js-d:`0022`|:py-d:`0022`|:rs-d:`0022`|
+|:prob:`22` |:c-d:`0022` |:cp-d:`0022`|:cs-d:`0022`|:js-d:`0022`|:py-d:`0022`|:rs-d:`0022`|
 +-----------+------------+------------+------------+------------+------------+------------+
 |:prob:`23` |            |            |            |            |:py-d:`0023`|            |
 +-----------+------------+------------+------------+------------+------------+------------+