C Day 1

.gitignore

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+*.exe

.vscode/launch.json

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+{
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "name": "(gdb) Start",
+      "type": "cppdbg",
+      "request": "launch",
+      "program": "${workspaceFolder}/c/day1.exe",
+      "args": [],
+      "stopAtEntry": false,
+      "cwd": "${workspaceFolder}/c/",
+      "environment": [],
+      "externalConsole": false,
+      "MIMode": "gdb",
+      "miDebuggerPath": "gdb",
+      "setupCommands": [
+        {
+          "text": "-enable-pretty-printing",
+          "ignoreFailures": true
+        }
+      ]
+    }
+  ]
+}

AdventOfCode.code-workspace

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+{
+	"folders": [
+		{
+			"path": "."
+		}
+	],
+	"settings": {
+		"files.associations": {
+			"*.lock": "yarnlock",
+			"stdlib.h": "c"
+		}
+	}
+}

c/build-all.ps1

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+gcc day1/*.c -o day1.exe -Og -g -Wall -Werror -std=c17

c/day1/main.c

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+// https://adventofcode.com/2021/
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define DAY 1
+#define INPUT_LENGTH 2000
+
+static int parsedInput[INPUT_LENGTH];
+
+void parseInput(char const *const input)
+{
+  char const *curLine = input;
+  unsigned int lineNum = 0;
+  while (curLine)
+  {
+    char const *nextLine = strchr(curLine, '\n');
+    int curLineLen = nextLine ? nextLine - curLine : strlen(curLine);
+    char *const tempStr = malloc(curLineLen + 1);
+    memcpy(tempStr, curLine, curLineLen);
+    tempStr[curLineLen] = '\0';
+
+    parsedInput[lineNum] = _atoi64(tempStr);
+
+    free(tempStr);
+
+    curLine = nextLine ? nextLine + 1 : NULL;
+    lineNum++;
+  }
+}
+
+char const *const part1()
+{
+  static const unsigned char MEASUREMENTS = 2;
+  int result = 0;
+  for (unsigned int i = MEASUREMENTS - 1; i < INPUT_LENGTH; i++)
+  {
+    if (parsedInput[i] > parsedInput[i - 1])
+    {
+      result++;
+    }
+  }
+  char *const resultString = malloc(sizeof(char) * 10);
+  sprintf(resultString, "%d", result);
+  return resultString;
+};
+char const *const part2()
+{
+  static const unsigned char MEASUREMENTS = 3;
+  int result = 0;
+  for (unsigned int i = MEASUREMENTS; i < INPUT_LENGTH; i++)
+  {
+    int measurementWindowA = parsedInput[i - 3] + parsedInput[i - 2] + parsedInput[i - 1];
+    int measurementWindowB = parsedInput[i - 2] + parsedInput[i - 1] + parsedInput[i - 0];
+
+    if (measurementWindowB > measurementWindowA)
+    {
+      result++;
+    }
+  }
+  char *const resultString = malloc(sizeof(char) * 10);
+  sprintf(resultString, "%d", result);
+  return resultString;
+};
+
+int main(void)
+{
+  char *const fileName = malloc(sizeof(char) * sizeof("dayXX/input.txt"));
+  sprintf(fileName, "day%d/input.txt", DAY);
+  FILE *inputFile = fopen(fileName, "r");
+
+  if (inputFile == NULL)
+  {
+    printf("Failed to open input file %s.\n", fileName);
+    return 1;
+  }
+
+  fseek(inputFile, 0, SEEK_END);
+  long length = ftell(inputFile);
+  fseek(inputFile, 0, SEEK_SET);
+  char *const input = malloc(length);
+  if (input != NULL)
+  {
+    fread(input, 1, length, inputFile);
+  }
+
+  fclose(inputFile);
+
+  parseInput(input);
+
+  printf("Day %d\n", DAY);
+  printf("Part 1:\n%s\n", part1());
+  printf("--------------\n");
+  printf("Part 2:\n%s\n\n", part2());
+  return 0;
+}