Day6 & Day7

day6/c/day6.c

@@ -0,0 +1,175 @@
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <omp.h>
+
+#define DIMENSION_MAX 512
+#define abs(a) ((a) < 0 ? (-(a)) : (a))
+
+typedef enum {
+    EMPTY,
+    OBSTRUCTION
+} tile_t;
+
+const int directions[][2] = {
+    {0, 1},
+    {1, 0},
+    {0, -1},
+    {-1, 0},
+};
+
+#define directions_len (sizeof(directions) / sizeof(directions[0]))
+
+int update(int pos[2], int dir[2], int* dir_idx, tile_t **map, int rows, int cols, int** visited, int* count);
+void next_dir(int dir[2], int *dir_idx);
+
+int main() {
+    char c;
+
+
+    tile_t **map = calloc(DIMENSION_MAX, sizeof(map[0]));
+    int rows = 0, columns = 0, i = 0;
+
+    map[rows] = calloc(DIMENSION_MAX, sizeof(map[0][0]));
+
+    int pos[2] = { 0 };
+    int dir[2] = { 0 };
+    int dir_idx = 0;
+    int mypos[2] = { 0 };
+    int mydir[2] = { 0 };
+    int mydir_idx = 0;
+
+    while ((c = getchar()) != EOF) {
+        switch (c) {
+            case '.':
+                map[rows][i] = EMPTY;
+                break;
+            case '#':
+                map[rows][i] = OBSTRUCTION;
+                break;
+            case '>':
+                mypos[0] = rows;
+                mypos[1] = i;
+                mydir[0] = 0;
+                mydir[1] = 1;
+                mydir_idx = 0;
+                break;
+            case '^':
+                pos[0] = rows;
+                pos[1] = i;
+                dir[0] = -1;
+                dir[1] = 0;
+                dir_idx = 3;
+                break;
+            default:
+                break;
+        }
+        i++;
+        if (c != '\n') {
+          continue;
+        }
+        columns = i - 1;
+
+        rows++;
+        map[rows] = calloc(DIMENSION_MAX, sizeof(map[0][0]));
+        i = 0;
+    }
+
+    int **visited = calloc(rows, sizeof(visited[0]));
+    for (i = 0; i < columns; i++) {
+        visited[i] = calloc(columns, sizeof(visited[0][0]));
+    }
+
+    int start[5] = {pos[0], pos[1], dir[0], dir[1], dir_idx};
+    int move_count = 0;
+    while (update(pos, dir, &dir_idx, map, rows, columns, visited, &move_count));
+
+    int count = 0;
+    for (i = 0; i < rows; i++) {
+        for (int j = 0; j < columns; j++) {
+            count += visited[i][j];
+        }
+    }
+
+    int count2 = 0;
+    for (i = 0; i < rows; i++) {
+        for (int j = 0; j < columns; j++) {
+            if (map[i][j] == EMPTY && visited[i][j] && !(i == start[0] && j == start[1])) {
+                int **tmp = calloc(rows, sizeof(tmp[0]));
+                for (int k = 0; k < rows; k++) {
+                    tmp[k] = calloc(columns, sizeof(tmp[0][0]));
+                }
+                pos[0] = start[0];
+                pos[1] = start[1];
+                dir[0] = start[2];
+                dir[1] = start[3];
+                dir_idx = start[4];
+                move_count = 0;
+                map[i][j] = OBSTRUCTION;
+                int result;
+                while((result = update(pos, dir, &dir_idx, map, rows, columns, tmp, &move_count)) == 1);
+                if (result == 2) {
+                    count2++;
+                }
+                map[i][j] = EMPTY;
+                for (int k = 0; k < rows; k++) {
+                    free(tmp[k]);
+                }
+                free(tmp);
+            }
+        }
+    }
+
+    for (i = 0; i < rows + 1; i++) {
+        free(map[i]);
+    }
+    free(map);
+
+
+    for (i = 0; i < columns; i++) {
+        free(visited[i]);
+    }
+    free(visited);
+
+    printf("%i\n", count);
+    printf("%i\n", count2);
+}
+
+int update(int pos[2], int dir[2], int* dir_idx, tile_t **map, int rows, int cols, int** visited, int *count) {
+    int y = pos[0] + dir[0];
+    int x = pos[1] + dir[1];
+
+    // Exiting map
+    if (y < 0 || x < 0 || y >= rows || x >= cols) {
+        return 0;
+    }
+
+    switch (map[y][x]) {
+        case OBSTRUCTION:
+            next_dir(dir, dir_idx);
+            break;
+        case EMPTY:
+            pos[0] = y;
+            pos[1] = x;
+            visited[y][x] = 1;
+            break;
+    }
+    (*count)++;
+
+    // Looping
+    if (*count > cols * rows * 4) {
+        return 2;
+    }
+
+    return 1;
+}
+
+void next_dir(int dir[2], int *dir_idx) {
+    (*dir_idx)++;
+    if (*dir_idx == directions_len) {
+        *dir_idx = 0;
+    }
+
+    dir[0] = directions[*dir_idx][0];
+    dir[1] = directions[*dir_idx][1];
+}