Advent-of-Code/2021/day13/solution-part1.c

#include <stdio.h>
#include <stdbool.h>
#include <string.h>
#include <stdlib.h>

#define ANSI_COLOR_RED     "\x1b[31m"
#define ANSI_COLOR_YELLOW  "\x1b[33m"
#define ANSI_COLOR_RESET   "\x1b[0m"

#define MAX(a, b) ((a) < (b) ? (b) : (a))
#define MIN(a, b) ((a) < (b) ? (a) : (b))

void printPaper( unsigned int width, unsigned int height, bool paper[width][height] ){
	for ( unsigned int y = 0; y < height; y++ ){
		printf("Line %i: ", y);
		for ( unsigned int x = 0; x < width; x++ ){
			if ( paper[x][y] == true ) printf("#");
			else printf(".");
		}
		printf("\n");
	}
}


void foldPaperX( unsigned int width, unsigned int height, unsigned int col, bool paper[width][height], bool newPaper[col][height]){
		for ( unsigned int x = 1; x < width - col; x++ )
			for ( unsigned int y=0; y < height; y++ )
				newPaper[col - x][y] = paper[col - x][y] || paper[col + x][y];
}

void foldPaperY( unsigned int width, unsigned int height, unsigned int row, bool paper[width][height], bool newPaper[width][row]){
	for ( unsigned int y=1; y < height - row; y++ )
		for ( unsigned int x = 0; x < width; x++ )
			newPaper[x][row - y] = ( paper[x][row - y] || paper[x][row + y] );
}

unsigned int countDots( unsigned int width, unsigned int height, bool paper[width][height] ){
	unsigned int count=0;
	for ( unsigned int y = 0; y < height; y++ )
		for ( unsigned int x = 0; x < width; x++ )
			if ( paper[x][y] == true ) count++;
	return count;
}

int main( int argc, char *argv[] ){
	if( argc == 2 ) {


		FILE *fp=fopen(argv[1], "r");

		unsigned int x=0,y=0,maxx=0,maxy=0;
		while ( fscanf( fp, "%i,%i\n",&x,&y )){
			maxx = MAX(maxx,x);
			maxy = MAX(maxy,y);
		}

		bool paper[maxx+1][maxy+1];
		memset(paper,0,sizeof(bool) * (maxx+1) * (maxy+1) );

		rewind(fp);
		while ( fscanf( fp, "%i,%i\n",&x,&y )){
			paper[x][y] = true;
		}

		printPaper( maxx+1, maxy+1, paper );
		printf("\n");

		char direction = '\0';
		unsigned int position = 0, dots = 0;
		fscanf(fp, "fold along %c=%i\n", &direction, &position);
		if ( direction == 'x' ){
			bool newPaper[position][maxy+1];
			foldPaperX(maxx+1,maxy+1,position, paper, newPaper);
			printPaper( position, maxy+1, newPaper );
			dots=countDots( position, maxy+1, newPaper );
		} else {
			bool newPaper[maxx+1][position];
			foldPaperY(maxx+1,maxy+1,position, paper, newPaper);
			printPaper( maxx+1, position, newPaper );
			dots=countDots( maxx+1, position, newPaper );
		}
		
		printf("\nThere are %i dots\n", dots);


		fclose(fp);



		return 0;
	} else {
		printf("You need to provide a file\n");
		return 1;
	}
}