init

2022/day6/p1/day6p1.c

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+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+
+int MARKER_LENGTH = 4;
+int MAX_LENGTH = 4095;
+
+int CountLines(char * FileName)
+{
+    char *Line = malloc(MAX_LENGTH);
+    int LineCount = 0;
+
+    FILE *File;
+    File = fopen(FileName, "r");
+
+    while (fgets(Line, MAX_LENGTH, File) != NULL)
+    {
+        LineCount++;
+    }
+
+    fclose(File);
+
+    return LineCount;
+}
+
+
+
+void GetLine(char * FileName, int LineNumber, char * Line)
+{
+
+    int CurrentLineNumber = 1;
+
+    FILE * File;
+    File = fopen(FileName, "r");
+
+    while (fgets(Line, MAX_LENGTH, File) != NULL)
+    {
+        if (CurrentLineNumber == LineNumber)
+            break;
+
+        else
+            CurrentLineNumber++;
+
+    }
+
+    fclose(File);
+}
+
+
+
+int main()
+{
+    char Marker[MARKER_LENGTH];
+
+    char FileName[] = "input.text";
+    int LineCount = CountLines(FileName);
+    int CurrentLine = 1;
+    char * Line = malloc(MAX_LENGTH);
+
+    do
+    {
+        // Clear Marker for new line
+        for (int i = 0; i < MARKER_LENGTH; i++)
+            Marker[i] = '\0';
+
+        GetLine(FileName, CurrentLine, Line);
+
+        for (int i = 0; i < strlen(Line); i++)
+        {
+            if (i < MARKER_LENGTH)
+            {
+                if (!Marker[i])
+                {
+                    Marker[i] = Line[i];
+                }
+            }
+            else
+            {
+                bool Repeat = false;
+
+                for (int a = 0; a < MARKER_LENGTH; a++)
+                {
+                    for (int b = 0; b < MARKER_LENGTH; b++)
+                    {
+                        if (Marker[a] == Marker[b] && a != b)
+                        {
+                            Repeat = true;
+                            break;
+                        }
+                    }
+                }
+
+                if (!Repeat)
+                {
+                    printf("Marker starts at character %d\n", i);
+                    for (int x = 0; x < MARKER_LENGTH; x++)
+                        printf("%c", Marker[x]);
+                    printf("\n");
+                    break;
+                }
+                else
+                {
+                    // Shift everything in Marker to the left by one
+                    Marker[0] = '\0';
+
+                    for (int x = 1; x < MARKER_LENGTH; x++)
+                        Marker[x-1] = Marker[x];
+
+                    Marker[3] = Line[i];
+                }
+            }
+        }
+
+        CurrentLine++;
+
+    }
+    while (CurrentLine <= LineCount);
+
+    return 1;
+}