116 lines
3.0 KiB
Zig
116 lines
3.0 KiB
Zig
const std = @import("std");
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const print = std.debug.print;
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const file = @embedFile("input");
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const LookingFor = enum {
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m_or_d,
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u,
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l,
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l_brace_mul,
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X,
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Y,
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o,
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t,
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apostrophe,
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l_brace_do,
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l_brace_do_or_n,
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r_brace_do,
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};
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pub fn main() !void {
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try std.testing.expectEqual(82857512, try parse(file));
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}
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fn parse(input: []const u8) !u32 {
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var state: LookingFor = .m_or_d;
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var total: u32 = 0;
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var intX_len: u8 = 0;
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var intY_len: u8 = 0;
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var enable = true;
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var enable_buff: bool = true;
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for (input, 0..) |c, i| switch (state) {
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.m_or_d => switch (c) {
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'm' => state = .u,
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'd' => state = .o,
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else => continue,
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},
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.u => switch (c) {
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'u' => state = .l,
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else => state = .m_or_d,
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},
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.l => switch (c) {
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'l' => state = .l_brace_mul,
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else => state = .m_or_d,
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},
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.o => switch (c) {
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'o' => state = .l_brace_do_or_n,
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else => state = .m_or_d,
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},
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.t => switch (c) {
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't' => state = .l_brace_do,
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else => state = .m_or_d,
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},
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.apostrophe => switch (c) {
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'\'' => state = .t,
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else => state = .m_or_d,
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},
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.l_brace_mul => switch (c) {
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'(' => {
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state = .X;
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intX_len = 0;
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intY_len = 0;
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},
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else => state = .m_or_d,
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},
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.l_brace_do => switch (c) {
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'(' => state = .r_brace_do,
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else => state = .m_or_d,
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},
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.l_brace_do_or_n => switch (c) {
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'(' => state = .r_brace_do,
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'n' => {
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enable_buff = false;
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state = .apostrophe;
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},
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else => state = .m_or_d,
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},
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.r_brace_do => switch (c) {
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')' => {
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enable = enable_buff;
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enable_buff = true;
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state = .m_or_d;
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},
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else => state = .m_or_d,
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},
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.X => switch (c) {
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',' => state = if (intX_len > 0) .Y else .m_or_d,
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'0'...'9' => if (intX_len == 3) {
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state = .m_or_d;
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} else {
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intX_len += 1;
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},
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else => state = .m_or_d,
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},
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.Y => switch (c) {
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')' => {
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state = .m_or_d;
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if (intY_len > 0) {
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if (!enable) continue;
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const x = try std.fmt.parseInt(u32, input[i - (intX_len + intY_len + 1) .. i - intY_len - 1], 10);
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const y = try std.fmt.parseInt(u32, input[i - intY_len .. i], 10);
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total += x * y;
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}
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},
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'0'...'9' => {
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if (intY_len == 3) {
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state = .m_or_d;
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continue;
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}
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intY_len += 1;
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},
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else => state = .m_or_d,
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},
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};
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return total;
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}
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