aoc2020/day8/part1/main.d

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2020-12-08 12:24:06 +01:00
import std;
void main()
{
"input".slurp!(string, int)("%s %s").executeProgramAndReturnAcc.writeln;
}
alias Instruction = Tuple!(string, int);
alias Program = Instruction[];
auto executeProgramAndReturnAcc(Program program)
{
int accumulator;
// dfmt off
alias operation = void delegate(ref ulong ip, int arg);
operation[string] operations = [
"nop" : (scope ref size_t ip, int arg) {ip += 1;},
"acc" : (scope ref size_t ip, int arg) { accumulator += arg; ip += 1; },
"jmp" : (scope ref size_t ip, int arg) {ip += arg;}
];
// dfmt on
void[0][size_t] seenIPs;
size_t ip = 0;
while (ip !in seenIPs)
{
seenIPs[ip] = [];
operations[program[ip][0]](ip, program[ip][1]);
}
return accumulator;
}
unittest
{
auto program = `nop +0
acc +1
jmp +4
acc +3
jmp -3
acc -99
acc +1
jmp -4
acc +6`.splitter("\n").filter!(not!empty)
.map!((line) {
auto opAndArg = line.split(" ");
return tuple(opAndArg[0], opAndArg[1].to!int);
})
.array;
assert(program.executeProgramAndReturnAcc == 5);
}