#include <stdio.h>
#include <stdlib.h>
typedef struct {
int position[2];
char character_direction;
} character_t;
character_t * get_new_position(char * string, character_t *character);
int main() {
// Create a basic character that starts at [0, 0], facing north
character_t *character = (character_t*)malloc(sizeof(character_t));
character->position[0] = 0;
character->position[1] = 0;
character->character_direction = 'N';
// Grab our puzzle input and parse it
FILE* f = fopen("input.txt", "r");
while(!feof(f)) {
char input[15];
fscanf(f, "%s", input);
get_new_position(input, character);
}
// The number of blocks away should be equal to the absolute difference between [x_1, y_1] and [x_0, y_0]
// Since we start at [0, 0] and measure how many blocks we move from there the answer is simply the
// absolute value of the sum of blocks moved in the x and y direction from our origin.
int difference = abs(character->position[0] + character->position[1]);
printf("Position: [%i, %i]\n", character->position[0], character->position[1]);
printf("Blocks away: %i\n", difference);
return 0;
}
character_t * get_new_position(char * string, character_t *character) {
int * character_position = character->position;
char character_direction = character->character_direction;
char turn_direction;
int steps;
sscanf(string, "%c%i", &turn_direction, &steps);
if(character_direction == 'N') {
if(turn_direction == 'R') {
character_direction = 'E';
character_position[0] += steps;
} else if(turn_direction == 'L') {
character_direction = 'W';
character_position[0] -= steps;
}
} else if(character_direction == 'S') {
if(turn_direction == 'R') {
character_direction = 'W';
character_position[0] -= steps;
} else if(turn_direction == 'L') {
character_direction = 'E';
character_position[0] += steps;
}
} else if(character_direction == 'E') {
if(turn_direction == 'R') {
character_direction = 'S';
character_position[1] -= steps;
} else if(turn_direction == 'L') {
character_direction = 'N';
character_position[1] += steps;
}
} else if(character_direction == 'W') {
if(turn_direction == 'R') {
character_direction = 'N';
character_position[1] += steps;
} else if(turn_direction == 'L') {
character_direction = 'S';
character_position[1] -= steps;
}
}
// Update the character to reflect the changes made
character->character_direction = character_direction;
character->position[0] = character_position[0];
character->position[1] = character_position[1];
return character;
}
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