Initial commit.

2015/one/solution.c

@@ -0,0 +1,50 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char** argv) {
+    /* Read the data. */
+    if (!(argc - 1)) exit(1);
+    FILE* f = fopen(argv[1], "rb");
+    if (!f) exit(2); // No file.
+
+    fseek(f, 0, SEEK_END);
+    long fsz = ftell(f);
+    fseek(f, 0, SEEK_SET);
+    if (fsz < 0) {
+        fclose(f);
+        exit(3); // Bad stream.
+    }
+
+    char* buf = malloc(fsz + 1);
+    if (!buf) {
+        fclose(f);
+        exit(4); // Bad malloc.
+    }
+
+    size_t nch = fread(buf, 1, fsz, f);
+    if (nch != fsz) {
+        free(buf);
+        exit(5); // Incomplete read.
+    }
+
+    buf[fsz] = '\0'; // Terminate.
+
+    int floor = 0;
+    int basement_pos = -1;
+
+    /* Parse the data. */
+    for (int i = 0; i < fsz; i++) {
+        switch (buf[i]) {
+            case '(': floor++; break;
+            case ')': floor--; break;
+            default:  continue;
+        }
+
+        if (floor == -1 && basement_pos == -1) { basement_pos = i + 1; }
+    }
+
+    printf("Part 1 solution: %d\n", floor);
+    printf("Part 2 solution: %d\n", basement_pos);
+
+    return 0;
+}