AoC 2020 VM

gistfile1.js

let parse = (entry) => {
    const op = entry.match(/(?<op>.*) (?<value>.*)/).groups;
    return {
        cnt: 0,
        op: op.op,
        value: parseInt(op.value)
    }
}

let runProgram = (program) => {
    program.forEach(x => x.cnt = 0);
    let stack = 0;
    let accu = 0;
    const cmd = {
      "nop": (value) => stack += 1,
      "acc": (value) => { accu += value; stack += 1; },
      "jmp": (value) => stack += value,
    }
    while(stack < program.length) {
        const op = program[stack];
        if(op.cnt > 0) { throw accu; }
        op.cnt += 1;
        cmd[op.op](op.value);
    }
    return accu;
}

let fixProgram = (program) => {
    const cmd = { "nop": "jmp", "jmp": "nop", "acc": "acc" };
    for(let i = 0; i < program.length; i++) {
        const op = program[i];
        if(op.op == "acc") { continue; }
        op.op = cmd[op.op];
         try { 
            const acc = runProgram(program);
            return acc;
        } catch { op.op = cmd[op.op]; }
    }
}

const content = $0.textContent.split("\n");
content.pop()
const program = content.map(parse);