day 7

1 files changed, 44 insertions, 0 deletions

diff --git a/src/day-7/part-2.zig b/src/day-7/part-2.zig
new file mode 100644
index 0000000..1ab8e82
--- /dev/null
+++ b/src/day-7/part-2.zig
@@ -0,0 +1,44 @@
+const std = @import("std");
+
+pub fn main() !void {
+    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+    defer _ = gpa.deinit();
+    const alloc = gpa.allocator();
+    
+    const path = "input.txt";
+    const fp = try std.fs.cwd().openFile(path, .{.mode = std.fs.File.OpenMode.read_only});
+    defer fp.close();
+    var reader = fp.reader();
+
+    var buffer: [256]u8 = undefined;
+
+    var beams = std.AutoHashMap(usize, u64).init(alloc);
+    defer beams.deinit();
+
+    while(try reader.readUntilDelimiterOrEof(&buffer, '\n')) |line| {
+        if(beams.count() == 0){
+            try beams.put(std.mem.indexOf(u8, line, "S").?, 1);
+            continue;
+        }
+
+        for(line, 0..) |l, i| {
+            if(l == '^' and beams.contains(i)){
+                const val = beams.get(i).?;
+                if(beams.contains(i + 1)) { try beams.put(i + 1, beams.get(i + 1).? + val); }
+                else try beams.put(i + 1, val);
+                if(beams.contains(i - 1)) { try beams.put(i - 1, beams.get(i - 1).? + val); }
+                else try beams.put(i - 1, val);
+
+                try beams.put(i, 0);
+            }
+        }        
+    }
+
+    var k = beams.iterator();
+    var timelines: u64 = 0;
+    while(k.next()) |o| {
+        timelines += o.value_ptr.*;
+    }
+
+    std.debug.print("{d}\n", .{timelines});
+}