From: Brendan Hansen <brendan.f.hansen@gmail.com>
Date: Thu, 10 Dec 2020 14:41:55 +0000 (-0600)
Subject: added day 10
X-Git-Url: https://git.brendanfh.com/?a=commitdiff_plain;h=cb232e37cbca4e27fc3ced90a1d24e9913b7de5e;p=onyx-aoc-2020.git

added day 10
---

diff --git a/day10.onyx b/day10.onyx
new file mode 100644
index 0000000..a2181d0
--- /dev/null
+++ b/day10.onyx
@@ -0,0 +1,54 @@
+#include_file "core/std/wasi"
+
+use package core
+use package core.str.reader as reader
+
+count_ending_paths :: proc (nums: [..] u32) -> u64 {
+    tally: [..] u64;
+    array.init(^tally, nums.count);
+    defer array.free(^tally);
+
+    for ^t: tally do *t = 0;
+    tally[nums.count - 1] = 1;
+
+    while i := cast(i32) (nums.count - 2); i >= 0 {
+        for diff: 1 .. 4 {
+            if i + diff >= nums.count do continue;
+
+            if nums[i + diff] - nums[i] <= 3 do tally[i] += tally[i + diff];
+        }
+
+        i -= 1;
+    }
+
+    return tally[0];
+}
+
+main :: proc (args: [] cstring) {
+    contents := file.get_contents("input/day10.txt");
+    defer cfree(contents.data);
+
+    file := reader.make(contents);
+
+    nums: [..] u32;
+    array.init(^nums);
+    defer array.free(^nums);
+
+    while !reader.empty(^file) {
+        array.push(^nums, reader.read_u32(^file)); 
+        reader.advance_line(^file);
+    }
+
+    // Slight hack, but having 0 in the array makes both parts easier
+    array.push(^nums, 0);
+
+    array.sort(^nums, cmp_asc);
+
+    diffs: [3] u32;
+    for ^d: diffs do *d = 0;
+    for i: 1 .. nums.count do diffs[nums[i] - nums[i - 1] - 1] += 1;
+    diffs[2] += 1;
+
+    printf("Diff prod: %i\n", diffs[0] * diffs[2]);
+    printf("Arrangements: %l\n", count_ending_paths(nums));
+}
diff --git a/input/day10.txt b/input/day10.txt
new file mode 100644
index 0000000..ccf88b7
--- /dev/null
+++ b/input/day10.txt
@@ -0,0 +1,92 @@
+17
+110
+146
+144
+70
+57
+124
+121
+134
+12
+135
+120
+19
+92
+6
+103
+46
+56
+93
+65
+14
+31
+63
+41
+131
+60
+73
+83
+71
+37
+85
+79
+13
+7
+109
+24
+94
+2
+30
+3
+27
+77
+91
+106
+123
+128
+35
+26
+112
+55
+97
+21
+100
+88
+113
+117
+25
+82
+129
+66
+11
+116
+64
+78
+38
+99
+130
+84
+98
+72
+50
+36
+54
+8
+34
+20
+127
+1
+137
+143
+76
+69
+111
+136
+53
+43
+140
+145
+49
+122
+18
+42
diff --git a/out.wasm b/out.wasm
index b4c5fb6..ac69ff6 100644
Binary files a/out.wasm and b/out.wasm differ