day 7 part 1

1 files changed, 84 insertions, 0 deletions

diff --git a/07/part1.c b/07/part1.c
new file mode 100644
index 0000000..316de25
--- /dev/null
+++ b/07/part1.c
@@ -0,0 +1,84 @@
+#include <algds/str.h>
+#include <algds/vec.h>
+#include <algds/hash_table.h>
+#include <string.h>
+
+#define PANIC do { \
+    fprintf(stderr, "panic at %s:%d\n", __FILE__, __LINE__); \
+    abort(); \
+} while (0)
+
+StringVector read_mat() {
+    StringVector mat;
+    StringVector_init(&mat);
+    while (1) {
+        char *l = fgetline(stdin);
+        if (!l) {
+            return mat;
+        }
+        if (strlen(l) == 0) {
+            return mat;
+        }
+        int len = strlen(l);
+        if (l[len - 1] == '\n') {
+            l[len - 1] = '\0';
+        }
+        StringVector_push_back(&mat, l);
+    }
+    return mat;
+}
+
+StringVector mat;
+int height;
+int width;
+
+Int2IntHashTable split(Int2IntHashTable input, const char* line, int *count) {
+    Int2IntHashTable new;
+    Int2IntHashTable_init(&new);
+    Int2IntHashTableIter iter = Int2IntHashTable_begin(&input);
+    for (; iter != NULL; iter = Int2IntHashTable_next(&input, iter)) {
+        int x = iter->key;
+        if (line[x] == '.') {
+            if (Int2IntHashTable_find(&new, x) == NULL) {
+                Int2IntHashTable_insert(&new, x, 0xff);
+            }
+        } else if (line[x] == '^') {
+            *count += 1;
+            if (x - 1 >= 0 && Int2IntHashTable_find(&new, x-1) == NULL) {
+                Int2IntHashTable_insert(&new, x-1, 0xff);
+            }
+            if (x + 1 < width && Int2IntHashTable_find(&new, x+1) == NULL) {
+                Int2IntHashTable_insert(&new, x+1, 0xff);
+            }
+        } else {
+            PANIC;
+        }
+    }
+    Int2IntHashTable_free(&input);
+    return new;
+} 
+
+int main() {
+    mat = read_mat();
+    height = mat.size;
+    width = strlen(mat.buffer[0]);
+    int ret = 0;
+    Int2IntHashTable beams;
+    Int2IntHashTable_init(&beams);
+    for (int i = 0; i < width; i++) {
+        if (mat.buffer[0][i] == 'S') {
+            Int2IntHashTable_insert(&beams, i, 0xff);
+        }
+    }
+    for (int i = 1; i < height; i++) {
+        beams = split(beams, mat.buffer[i], &ret);
+    }
+    printf("%d\n", ret);
+
+    for (int i = 0; i < height; i++) {
+        free((void*)mat.buffer[i]);
+    }
+    StringVector_free(&mat);
+    Int2IntHashTable_free(&beams);
+    return 0;
+}
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