Day 1 part 2 HEAD master

1 files changed, 65 insertions, 0 deletions

diff --git a/1/part2.zig b/1/part2.zig
new file mode 100644
index 0000000..aad482c
--- /dev/null
+++ b/1/part2.zig
@@ -0,0 +1,65 @@
+const std = @import("std");
+
+pub fn main() !void {
+    var file = try std.fs.cwd().openFile("input", .{});
+    defer file.close();
+
+    var reader = file.reader();
+    var output: [100]u8 = undefined;
+    var output_fbs = std.io.fixedBufferStream(&output);
+    const writer = output_fbs.writer();
+
+    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+    const allocator = gpa.allocator();
+    var list1 = std.ArrayList(i32).init(allocator);
+    defer list1.deinit();
+    var map = std.AutoHashMap(i32, i32).init(allocator);
+    defer map.deinit();
+
+    while (true) {
+        reader.streamUntilDelimiter(writer, '\n', null) catch |err| {
+            switch (err) {
+                error.EndOfStream => {
+                    output_fbs.reset(); // clear buffer before exit
+                    break;
+                }, // file read till the end
+                else => {
+                    std.debug.print("Error while reading file: {any}\n", .{err});
+                    return err;
+                },
+            }
+        };
+
+        const line = output_fbs.getWritten();
+        std.debug.print("Line: {s}\n", .{line});
+        var split = std.mem.splitSequence(u8, line, "   ");
+
+        // TODO
+        const on = split.next().?;
+        const tw = split.next().?;
+        const one: i32 = try std.fmt.parseInt(i32, on, 10);
+        const two: i32 = try std.fmt.parseInt(i32, tw, 10);
+
+        try list1.append(one);
+
+        const val = map.get(two) orelse 0;
+
+        try map.put(two, val + 1);
+
+        // since steamUntilDelimiter keeps appending the read bytes to the buffer
+        // we should clear it on every iteration so that only individual lines are
+        // displayed on each iteration.
+        output_fbs.reset();
+    }
+
+    var similarity_score: i32 = 0;
+
+    for (list1.items) |item| {
+        const val = map.get(item) orelse 0;
+        similarity_score += item * val;
+    }
+
+    std.debug.print("Similarity score: {d}\n", .{similarity_score});
+
+    std.debug.print("Hello, {s}!\n", .{"World"});
+}