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const std = @import("std");
const aoc = @import("aoc");
const Console = @import("console8").Console;
fn runTillRepeat(console: *Console, instlist: *std.ArrayList(u64), swapon: ?u64) !void {
while (try console.parseNext()) |_inst| {
var inst = _inst;
aoc.debugfmt("{:<5}: {s} {d}\n", .{ console.instructptr, inst.opcode, inst.argval });
if (std.mem.indexOfScalar(u64, instlist.items, console.instructptr) != null) {
return;
}
if (swapon != null and swapon.? == console.instructptr) {
inst.opfunc = switch (inst.opfunc) {
Console.jumpInstruction => Console.nopInstruction,
Console.nopInstruction => Console.jumpInstruction,
else => unreachable,
};
}
try instlist.append(console.instructptr);
try console.exec(&inst);
}
}
fn part1(allocator: std.mem.Allocator, input: []u8, args: [][]u8) !?[]u8 {
_ = args;
var console = try Console.init(input, allocator);
defer console.deinit();
var instlist = std.ArrayList(u64).init(allocator);
defer instlist.deinit();
try runTillRepeat(&console, &instlist, null);
return try std.fmt.allocPrint(allocator, "{d}", .{console.accumulator});
}
fn part2(allocator: std.mem.Allocator, input: []u8, args: [][]u8) !?[]u8 {
_ = args;
var console = try Console.init(input, allocator);
defer console.deinit();
var instlist = std.ArrayList(u64).init(allocator);
defer instlist.deinit();
try runTillRepeat(&console, &instlist, null);
for (instlist.items) |inst| {
if (std.mem.eql(u8, "acc"[0..3], console.instlist[inst][0..3]))
continue;
var sim_seen = std.ArrayList(u64).init(allocator);
defer sim_seen.deinit();
console.reset();
//std.debug.print("Swapping instruction: {:<5}: {}\n", .{ inst, console.instlist[inst] });
runTillRepeat(&console, &sim_seen, inst) catch {};
if (console.jumpAddr == console.instlist.len or console.instructptr == console.instlist.len) {
return try std.fmt.allocPrint(allocator, "{d}", .{console.accumulator});
}
}
return null;
}
pub const main = aoc.main(part1, part2, .{ "1766", "1639" });
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