99 lines
2.7 KiB
Zig
99 lines
2.7 KiB
Zig
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const std = @import("std");
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const mem = std.mem;
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const fmt = std.fmt;
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const CharList = std.ArrayList(u8);
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const input = @embedFile("input");
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const n_crates = 9;
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fn parseCrates(input_iterator: *mem.SplitIterator(u8), comptime n: u8, allocator: mem.Allocator) []CharList {
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// Return value
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var crates = allocator.alloc(CharList, n) catch unreachable;
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for (crates) |*crate| {
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crate.* = CharList.init(allocator);
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}
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// Make sure it's pointing to the start
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input_iterator.reset();
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while (input_iterator.next()) |line| {
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// Parse until empty line
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if (line.len == 0) break;
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// Keep track of which crate we are in
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var index: usize = 0;
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for (line) |char, i| {
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switch (char) {
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'A'...'Z' => crates[index].insert(0, char) catch unreachable,
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else => index = i / 4,
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}
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}
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}
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return crates;
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}
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fn destroyCrates(crates: []CharList) void {
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for (crates) |*crate| {
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crate.*.deinit();
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}
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}
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pub fn main() !void {
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var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
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defer arena.deinit();
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const allocator = arena.allocator();
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var input_iterator = mem.split(u8, input, "\n");
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var crates = parseCrates(&input_iterator, n_crates, allocator);
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//defer destroyCrates(crates);
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while (input_iterator.next()) |line| {
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if (line.len == 0) continue;
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// Print the state
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for (crates) |crate, i| {
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std.debug.print("{d} : {s}\n", .{ i, crate.items });
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}
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// Parsing the line to get action
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var line_iterator = mem.split(u8, line, " ");
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// n, src, dst
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var numbers = [_]u8{undefined} ** 3;
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var index: usize = 0;
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while (line_iterator.next()) |word| {
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// Get a number and asign or go to next word
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numbers[index] = fmt.parseInt(u8, word, 10) catch continue;
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if (index == 3) {
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std.debug.print("Word parsing error, index out of bounds", .{});
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unreachable;
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}
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index += 1;
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}
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// Performing the action
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var i: usize = 0;
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const n = numbers[0];
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const src = numbers[1] - 1;
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const dst = numbers[2] - 1;
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std.debug.print("Move {} from {} to {}\n", .{n, src, dst});
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var tmp_crates = CharList.init(allocator);
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while (i < n) : (i += 1) {
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tmp_crates.insert(0, crates[src].pop()) catch unreachable;
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}
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crates[dst].appendSlice(tmp_crates.items) catch unreachable;
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}
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// Printing the final state
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for (crates) |crate, i| {
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std.debug.print("{d} : {s}\n", .{ i, crate.items });
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}
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}
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