day 7

day7.c

@@ -0,0 +1,178 @@
+#include "lib.h"
+
+#define DBG 0
+
+static
+ch input[32768] = {
+#embed "day7_input.txt"
+};
+
+static
+ch test[512] = {
+#embed "day7_test.txt"
+};
+
+typedef struct { ch l[64]; } line;
+static_assert(sizeof(line) == 0x40);
+
+alignas(0x40) static
+struct {
+    line padstart[4];
+    num file_stride;
+    num stride;
+    num _extra[6];
+    union { line l; struct { ch s[16]; num n; }; } result;
+    line padend;
+} m;
+static_assert(offsetof(typeof(m),result) % 64 == 0);
+static_assert(offsetof(typeof(m),padend) % 64 == 0);
+
+alignas(4096) ch buf1[256];
+alignas(4096) num buf[256];
+
+static
+num do_part1(size_t file_len, ch file[file_len]) {
+    m = (typeof(m)){ };
+    m.result.n = 0;
+#if DBG
+        pnl();
+#endif
+
+    memset(buf1, 0, sizeof(buf1));
+
+    m.file_stride = findc(file, '\n', file_len) - file;
+    num linecnt = (findc(file, 0, file_len) - file) / m.file_stride;
+#if DBG
+    print("stride "); printd(m.file_stride); pnl();
+    print("lines  "); printd(linecnt); pnl();
+#endif
+
+    num s_pos = findc(file, 'S', - 1) - 1 - file;
+    buf1[s_pos] = '|';
+    num line = 2;
+    do {
+        ch *l = file + line * m.file_stride;
+        for (num col = 0; col < m.file_stride - 1; col++) {
+            ch c = l[col];
+            if (c == '^') {
+                m.result.n += buf1[col] > 0;
+                buf1[col-1] |= buf1[col];
+                buf1[col+1] |= buf1[col];
+                buf1[col] = 0;
+            }
+        }
+#if DBG
+        for (num col = 0; col < m.file_stride; col++) {
+            if (buf1[col] == '|') print("|");
+            else if (l[col] == '^') print("^");
+            else print(" ");
+        }
+        pnl();
+#endif
+        line+=2;
+    } while (line < linecnt);
+
+    return m.result.n;
+}
+
+static
+num do_part2(size_t file_len, ch file[file_len]) {
+    m = (typeof(m)){ };
+#if DBG
+        pnl();
+#endif
+
+    memset(buf, 0, sizeof(buf));
+
+    m.file_stride = findc(file, '\n', file_len) - file;
+    num linecnt = (findc(file, 0, file_len) - file) / m.file_stride;
+#if DBG
+    print("stride "); printd(m.file_stride); pnl();
+    print("lines  "); printd(linecnt); pnl();
+#endif
+
+    num s_pos = findc(file, 'S', - 1) - 1 - file;
+    buf[s_pos] = 1;
+    num line = 2;
+    do {
+        ch *l = file + line * m.file_stride;
+        for (num col = 0; col < m.file_stride - 1; col++) {
+            ch c = l[col];
+            if (c == '^') {
+                buf[col-1] += buf[col];
+                buf[col+1] += buf[col];
+                buf[col] = 0;
+            }
+        }
+        for (num col = 0; col < m.file_stride; col++) {
+            num v = buf[col];
+#if DBG
+            if (l[col] == '^') print(" ");
+            else if (v >> 32) print("█");
+            else if (v >> 16) print("▓");
+            else if (v >>  8) print("▒");
+            else if (v >>  4) print("░");
+            else if (v >>  2) print("-");
+            else if (v >>  0) print(".");
+            else print(" ");
+#endif
+        }
+#if DBG
+        pnl();
+#endif
+        line+=2;
+    } while (line < linecnt);
+
+    m.result.n = 0;
+    for (num col = 0; col < m.file_stride; col++) {
+        m.result.n += buf[col];
+    }
+
+    return m.result.n;
+}
+
+#define RUN_TEST1 1
+#define RUN_PART1 1
+#define RUN_TEST2 1
+#define RUN_PART2 1
+
+#define TEST1_EXPECT 21
+#define TEST2_EXPECT 40
+
+void run() {
+#if RUN_TEST1
+    print("PART 1 TEST: ");
+    if (num v = do_part1(countof(test), test); v != TEST1_EXPECT) {
+        print("FAILED (got ");
+        printd(v);
+        print(", expected " xstr(TEST1_EXPECT) ")\n");
+    } else {
+        print("PASSED\n");
+    }
+#endif
+
+#if RUN_PART1
+    print("PART 1 RESULT: ");
+    printd(do_part1(countof(input), input));
+    print("\n");
+#endif
+
+#if RUN_TEST2
+    print("PART 2 TEST: ");
+    if (num v = do_part2(countof(test), test); v != TEST2_EXPECT) {
+        print("FAILED (got ");
+        printd(v);
+        print(", expected " xstr(TEST2_EXPECT) ")\n");
+    } else {
+        print("PASSED\n");
+    }
+#endif
+
+#if RUN_PART2
+    print("PART 2 RESULT: ");
+    printd(do_part2(countof(input), input));
+    print("\n");
+#endif
+
+    exit_group(0);
+}