day 5

1 files changed, 58 insertions, 0 deletions

diff --git a/src/day-5/part-2.zig b/src/day-5/part-2.zig
new file mode 100644
index 0000000..a1ff825
--- /dev/null
+++ b/src/day-5/part-2.zig
@@ -0,0 +1,58 @@
+const std = @import("std");
+
+const val = struct { n: u64, open: bool }; 
+
+pub fn asc_val(_: void, a: val, b:val) bool {
+    return a.n < b.n;
+}
+
+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 list = std.ArrayList(val).init(alloc);
+    defer list.deinit();
+
+    var buffer: [256]u8 = undefined;
+
+    while(try reader.readUntilDelimiterOrEof(&buffer, '\n')) |line| {
+
+        if(line.len == 0) break;
+
+        if(std.mem.indexOf(u8, line, "-")) |ind| {
+            const low: u64 = try std.fmt.parseInt(u64, line[0 .. ind], 10);
+            const high: u64 = try std.fmt.parseInt(u64, line[ind + 1 ..], 10);
+
+            //no clue why this is required, since both are inclusive it should be fine, maybe better sorting would work here but im not certain
+            if(low == high){
+                continue;
+            }
+
+            try list.append(.{.n = high, .open = false});
+            try list.append(.{.n = low, .open = true});
+        }
+    }
+
+    std.mem.sort(val, list.items, {}, asc_val);
+
+    var count: i64 = 0;
+    var last_val: u64 = 0;
+    var fresh: u64 = 0;
+    for(list.items) |v| {
+        if(v.open){
+            count += 1; 
+            if(count == 1) last_val = v.n;
+        } else { 
+            count -= 1;
+            if(count == 0) fresh += v.n - last_val + 1;
+        }        
+    }
+
+    std.debug.print("{d}\n", .{fresh});
+}