89 lines
2.1 KiB
D
89 lines
2.1 KiB
D
import std;
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void main()
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{
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"input".slurp!(string, int)("%s %s").fixProgramAndReturnAcc[0].writeln;
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}
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alias Instruction = Tuple!(string, int);
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alias Program = Instruction[];
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auto executeProgramAndReturnAcc(Program program)
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{
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int accumulator;
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// dfmt off
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alias operation = void delegate(ref ulong ip, int arg);
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operation[string] operations = [
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"nop" : (scope ref size_t ip, int arg) {ip += 1;},
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"acc" : (scope ref size_t ip, int arg) { accumulator += arg; ip += 1; },
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"jmp" : (scope ref size_t ip, int arg) {ip += arg;}
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];
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// dfmt on
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void[0][size_t] seenIPs;
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size_t ip = 0;
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while (ip !in seenIPs && ip < program.length)
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{
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seenIPs[ip] = [];
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operations[program[ip][0]](ip, program[ip][1]);
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}
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return tuple(accumulator, ip == program.length);
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}
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unittest
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{
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auto program = `nop +0
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acc +1
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jmp +4
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acc +3
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jmp -3
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acc -99
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acc +1
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jmp -4
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acc +6`.splitter("\n").filter!(not!empty)
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.map!((line) {
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auto opAndArg = line.split(" ");
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return tuple(opAndArg[0], opAndArg[1].to!int);
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})
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.array;
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assert(program.executeProgramAndReturnAcc == tuple(5, false));
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}
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auto fixProgramAndReturnAcc(Program program)
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{
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return program.enumerate
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.map!((indexedInstruction) {
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if (indexedInstruction.value[0] == "acc")
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return tuple(0, false);
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else if (indexedInstruction.value[0] == "nop")
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indexedInstruction.value[0] = "jmp";
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else
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indexedInstruction.value[0] = "nop";
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return (program[0 .. indexedInstruction.index]
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~ [indexedInstruction.value] ~ program[indexedInstruction.index + 1 .. $])
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.executeProgramAndReturnAcc;
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})
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.find!(result => result[1])
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.front;
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}
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unittest
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{
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auto program = `nop +0
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acc +1
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jmp +4
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acc +3
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jmp -3
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acc -99
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acc +1
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jmp -4
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acc +6`.splitter("\n").filter!(not!empty)
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.map!((line) {
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auto opAndArg = line.split(" ");
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return tuple(opAndArg[0], opAndArg[1].to!int);
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})
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.array;
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assert(program.fixProgramAndReturnAcc == tuple(8, true));
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}
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