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const std = @import("std");
const data = @embedFile("day07");
var general_purpose_allocator = std.heap.GeneralPurposeAllocator(.{}){};
const gpa = general_purpose_allocator.allocator();
const eql = std.mem.eql;
pub fn main() !void {
defer std.debug.assert(!general_purpose_allocator.deinit());
var lines = std.mem.tokenize(u8, data, "\n");
var fs = std.StringHashMap(usize).init(gpa);
defer {
var keyiter = fs.keyIterator();
while (keyiter.next()) |key| {
gpa.free(key.*);
}
fs.deinit();
}
var cwd = std.ArrayList([]const u8).init(gpa);
defer cwd.deinit();
_ = lines.next();
var root = try gpa.dupe(u8, "/");
while (lines.next()) |line| {
if (line.len == 0)
break;
if (std.mem.startsWith(u8, line, "$ cd")) {
var parts = std.mem.tokenize(u8, line, " ");
_ = parts.next();
_ = parts.next();
var dir = parts.next().?;
if (eql(u8, dir, "..")) {
_ = cwd.pop();
} else {
try cwd.append(dir);
}
} else if (eql(u8, line, "$ ls")) {
while (lines.peek()) |dirline| {
if (dirline[0] == '$') break;
_ = lines.next();
if (std.mem.startsWith(u8, dirline, "dir ")) continue;
var parts = std.mem.split(u8, dirline, " ");
var size = try std.fmt.parseInt(usize, parts.first(), 10);
try fs.put(root, (fs.get(root) orelse 0) + size);
var fullpath = std.ArrayList(u8).init(gpa);
defer fullpath.deinit();
for (cwd.items) |segment| {
try fullpath.append('/');
try fullpath.appendSlice(segment);
var s = try gpa.dupe(u8, fullpath.items);
var v = try fs.getOrPut(s);
if (!v.found_existing) {
v.value_ptr.* = size;
} else {
v.value_ptr.* += size;
gpa.free(s);
}
}
}
}
}
var part1: usize = 0;
var iter = fs.iterator();
while (iter.next()) |entry| {
if (entry.value_ptr.* <= 100_000)
part1 += entry.value_ptr.*;
}
var needed: usize = 30000000 - (70000000 - fs.get(root).?);
var part2: usize = 70000000;
var iter2 = fs.iterator();
while (iter2.next()) |entry| {
if (entry.value_ptr.* > needed)
part2 = std.math.min(part2, entry.value_ptr.*);
}
std.debug.print("{}\n{}\n", .{part1, part2});
}
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