Advent-of-Code/2021/day7/solution-part2.c

#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <math.h>

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

double average(unsigned int length, unsigned int *list) {

   double sum = 0.0;

   /* access all the arguments assigned to valist */
   for (unsigned int i = 0; i < length; i++) {
	   sum += list[i];
   }
	

   return sum/length;
}

unsigned int totalDistance(unsigned int crabLength, unsigned int *crabs, unsigned int target){
	unsigned int totalDistance = 0;
	for (unsigned int i = 0; i < crabLength; i++){
		unsigned int distance = abs((int)crabs[i] - (int)target);
		unsigned int cost = distance * (distance + 1) / 2;
		//printf( "Move from %i to %i: %i fuel\n", crabs[i], target, cost );
		totalDistance += cost;
	}
	return totalDistance;
}


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


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

		unsigned int count=0;
		unsigned int no;
		char ch;
		// Count the number of crab positions
		while ( fscanf( fp, "%i%c", &no, &ch ) ){
			count++;
			if ( ch == '\n' ) break;
		}

		rewind(fp);

		unsigned int min = ~0;
		unsigned int max = 0;
		unsigned int crabs[count];

		for (unsigned int i= 0; i<count; i++ ){
			fscanf( fp, "%i%c", &no, &ch );
			crabs[i] = no;
			min = MIN( min, no );
			max = MAX( max, no );
		}





		unsigned int smallestCost = ~0;
		for ( unsigned int i = 0; i <= max; i++ ){
			smallestCost = MIN( smallestCost, totalDistance( count, crabs, i ) );
		}


		printf("Smallest Cost: %i\n", smallestCost);




		fclose(fp);



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