Committing days 1-4

01/01-part2.c

@@ -0,0 +1,133 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+// How much memory to allocate for each line
+#define MAX_LINE_LEN 200
+
+#define DEFAULT_FILE "input.txt"
+
+// Returns 0 if a string is not a number (e.g. 'two')
+// Otherwise, returns the equivilant ascii character digit.
+// Only works for single digits.
+// Only accepts lower case.
+char parse_num(char *str)
+{
+    const char *num_strings[10] =  { "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine" };
+
+    // The lengths of the strings above, 
+    const uint8_t num_string_lens[10] =  { 4, 3, 3, 5, 4, 4, 3, 5, 5, 4 };
+
+    bool possible_nums[10] = { [0 ... 9] = true };
+    uint8_t num_idx = 0;
+    uint8_t char_incriment = 0;
+    char current;
+    bool result_still_possible = false;
+
+    for (char_incriment = 0; char_incriment < 6; char_incriment++)
+    {
+        // Grab out next character in the string
+        current = *(str + char_incriment);
+
+        for (num_idx = 0; num_idx < 10; num_idx++)
+        {
+            if (!possible_nums[num_idx]) continue;
+
+            // If we have passed the end of our number string and every character has matched,
+            // then we return our valid character.
+            if (char_incriment == num_string_lens[num_idx] && possible_nums[num_idx]) return (num_idx + '0');
+
+            // If the character is not the letter it should be, disqualify this number.
+            // e.g. if num_idx == 1 and char_incriment == 2, current should equal 'e'
+            // because 'e' is the 3rd number in the word 'one.'
+            if (current != num_strings[num_idx][char_incriment]) possible_nums[num_idx] = false;
+            else result_still_possible = true;
+        }
+        if (!result_still_possible) return 0;
+    }
+
+    return 0;
+}
+
+// Returns a string of the next line.
+// Remember to free() this after you're finished.
+// Limited by MAX_LINE_LEN (I'm lazy.)
+char *next_line(FILE *file)
+{
+    char *strbuf = malloc(sizeof(char) * MAX_LINE_LEN);
+    uint8_t idx = 0;
+    char current = 0;
+
+    while (current != '\n' && current != EOF)
+    {
+        current = fgetc(file);
+        strbuf[idx] = current;
+        idx++;
+    }
+
+    return strbuf;
+}
+
+int main(int argc, char **argv) {
+
+    // Get filename as an argument
+    char *path = (argc > 1) ? argv[1] : DEFAULT_FILE;
+
+    if (!path)
+    {
+        printf("Requires input file.\n");
+        return 1;
+    }
+
+    FILE *file = fopen(path, "r");
+
+    if (!file)
+    {
+        printf("Could not find file.");
+        return 1;
+    }
+
+    int8_t firstdigit = -1;
+    int8_t lastdigit = -1;
+    int8_t parsed_num = -1;
+    uint32_t sum = 0;
+    char current = 0;
+    char *strbuf = next_line(file);
+    uint8_t strbuf_idx = 0;
+
+    while (current != EOF)
+    {
+        parsed_num = parse_num(strbuf + strbuf_idx);
+        current = strbuf[strbuf_idx++];
+
+        if (current == '\n')
+        {
+            if (lastdigit == -1) lastdigit = firstdigit;
+            sum += (firstdigit * 10) + lastdigit;
+            firstdigit = -1;
+            lastdigit = -1;
+            strbuf_idx = 0;
+            free(strbuf);
+            strbuf = next_line(file);
+            continue;
+        }
+
+        if (parsed_num != 0) current = parsed_num;
+
+        if (current < '0' || current > '9') continue;
+
+        if (firstdigit == -1)
+        {
+            firstdigit = current - '0';
+        }
+        else
+        {
+            lastdigit = current - '0';
+        }
+    }
+
+    printf("Sum: %d\n", sum);
+
+    return 0;
+}

01/01.c

@@ -0,0 +1,57 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+
+int main(int argc, char **argv) {
+
+    // Get filename as an argument, defaults to "input.txt"
+    char *path = (argc > 1) ? argv[1] : "input.txt";
+
+    if (!path)
+    {
+        printf("Requires input file.\n");
+        return 1;
+    }
+
+    FILE *file = fopen(path, "r");
+
+    if (!file)
+    {
+        printf("Could not find file.");
+        return 1;
+    }
+
+    int8_t firstdigit = -1;
+    int8_t lastdigit = -1;
+    uint32_t sum = 0;
+    char current = 0;
+
+    while (current != EOF)
+    {
+        current = fgetc(file);
+
+        if (current == '\n')
+        {
+            if (lastdigit == -1) lastdigit = firstdigit;
+            sum += (firstdigit * 10) + lastdigit;
+            firstdigit = -1;
+            lastdigit = -1;
+            continue;
+        }
+
+        if (current < '0' || current > '9') continue;
+
+        if (firstdigit == -1)
+        {
+            firstdigit = current - '0';
+        }
+        else
+        {
+            lastdigit = current - '0';
+        }
+    }
+
+    printf("Sum: %d\n", sum);
+
+    return 0;
+}

01/01test.c

@@ -0,0 +1,60 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+// Returns -1 if a string is not a number (e.g. 'two')
+// Otherwise, returns the number.
+// Only works for single digits.
+// Only accepts lower case.
+int8_t parse_num(char *str)
+{
+    const char *num_strings[10] =  { "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine" };
+
+    // The lengths of the strings above, 
+    const uint8_t num_string_lens[10] =  { 4, 3, 3, 5, 4, 4, 3, 5, 5, 4 };
+
+    bool possible_nums[10] = { [0 ... 9] = true };
+    uint8_t num_idx = 0;
+    uint8_t char_incriment = 0;
+    char current;
+    bool result_still_possible = false;
+
+    for (char_incriment = 0; char_incriment < 6; char_incriment++)
+    {
+        // Grab out next character in the string
+        current = *(str + char_incriment);
+
+        for (num_idx = 0; num_idx < 10; num_idx++)
+        {
+            if (!possible_nums[num_idx]) continue;
+
+            // If we have passed the end of our number string and every character has matched,
+            // then we return our valid character.
+            if (char_incriment == num_string_lens[num_idx] && possible_nums[num_idx]) return num_idx;
+
+            // If the character is not the letter it should be, disqualify this number.
+            // e.g. if num_idx == 1 and char_incriment == 2, current should equal 'e'
+            // because 'e' is the 3rd number in the word 'one.'
+            if (current != num_strings[num_idx][char_incriment]) possible_nums[num_idx] = false;
+            else result_still_possible = true;
+        }
+        if (!result_still_possible) return -1;
+    }
+
+    return -1;
+}
+
+int main(int argc, char **argv) {
+
+    const char *num_strings[10] =  { "zerorr", "oneqw", "twoqw", "threere", "fourer", "fiveer", "sixer", "sevener", "eighter", "nineer" };
+
+    uint8_t i = 0;
+
+    for (i = 0; i < 10; i++)
+    {
+        printf("%d\n", parse_num(num_strings[i]));
+    }
+
+    return 0;
+}

01/input2.txt

@@ -0,0 +1,4 @@
+zero1
+1zero
+asdfone
+asdfoneasdfoneasdf