C 2024 day 18 part 1

c/2024/18/ram_run.c

@@ -0,0 +1,99 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+
+#include "../../lib/aoc.h"
+
+#define DIMENSION 71
+#define QUEUE_LENGTH 200
+
+typedef struct Node {
+  int x;
+  int y;
+  char c;
+  int cost;
+} Node;
+
+typedef struct Grid {
+  Node grid[DIMENSION][DIMENSION];
+} Grid;
+
+int main() {
+  char *line;
+  Grid g;
+
+  for (int i = 0; i < DIMENSION; i++) {
+    for (int j = 0; j < DIMENSION; j++) {
+      g.grid[i][j].x = i;
+      g.grid[i][j].y = j;
+      g.grid[i][j].c = '.';
+      g.grid[i][j].cost = -1;
+    }
+  }
+
+  int x, y;
+  int i = 0;
+
+  while ((line = aoc_read_line()) != NULL) {
+    sscanf(line, "%d,%d", &x, &y);
+    if (i++ < 1024) g.grid[x][y].c = '#';
+  }
+
+  Node* queue[QUEUE_LENGTH];
+  queue[0] = &(g.grid[0][0]);
+  int queue_start = 0;
+  int queue_end = 1;
+
+  g.grid[0][0].c = '*';
+  g.grid[0][0].cost = 0;
+
+  while (queue_start != queue_end) {
+    // get first element of queue
+    Node* n = queue[queue_start++];
+    queue_start %= QUEUE_LENGTH;
+    n->c = ' ';
+    // add its neighbors to the queue
+    if (n->x - 1 >= 0 && g.grid[n->x - 1][n->y].c == '.') {
+      g.grid[n->x - 1][n->y].c = '*';
+      g.grid[n->x - 1][n->y].cost = n->cost + 1;
+      queue[queue_end++] = &(g.grid[n->x - 1][n->y]);
+      queue_end %= 200;
+    }
+
+    if (n->y - 1 >= 0 && g.grid[n->x][n->y - 1].c == '.') {
+      g.grid[n->x][n->y - 1].c = '*';
+      g.grid[n->x][n->y - 1].cost = n->cost + 1;
+      queue[queue_end++] = &(g.grid[n->x][n->y - 1]);
+      queue_end %= 200;
+    }
+
+    if (n->x + 1 < DIMENSION && g.grid[n->x + 1][n->y].c == '.') {
+      g.grid[n->x + 1][n->y].c = '*';
+      g.grid[n->x + 1][n->y].cost = n->cost + 1;
+      queue[queue_end++] = &(g.grid[n->x + 1][n->y]);
+      queue_end %= 200;
+    }
+
+    if (n->y + 1 < DIMENSION && g.grid[n->x][n->y + 1].c == '.') {
+      g.grid[n->x][n->y + 1].c = '*';
+      g.grid[n->x][n->y + 1].cost = n->cost + 1;
+      queue[queue_end++] = &(g.grid[n->x][n->y + 1]);
+      queue_end %= 200;
+    }
+  }
+
+  /*
+  for (int i = 0; i < DIMENSION; i++) {
+    for (int j = 0; j < DIMENSION; j++) {
+      printf("%c", g.grid[j][i].c);
+    }
+    printf("\n");
+  }
+  */
+
+  printf("Part 1: %d", g.grid[DIMENSION - 1][DIMENSION - 1].cost);
+
+  aoc_free();
+  exit(0);
+}