protected override string?SolvePartOne()
{
var p = new Day19.OpCodeComputer(Input);
while (p.RunOperation())
{
// Run it
}
return(p.registers[0].ToString());
}
public Day21() : base(21, 2018, "Chronal Conversion")
{
p = new Day19.OpCodeComputer(Input);
}
protected override string?SolvePartTwo()
{
// This is supposed to be a reduction problem where
// the assembly is broken down and determine what is being done
var p = new Day19.OpCodeComputer(Input);
/*
* Initial breakdown:
* goto A, r4=16, r4++ (r4=17 in the end)
* C: r1 = 1, r4++
* E: r2 = 1, r4++
* D: r3 = r1 * r2
* if (r3 == r5) r3=1 else r3=0, r4++
* r4 += r3, r4++
* r4 += 1, r4++
* r0 += r1, r4++
* r2 += 1, r4++
* if (r2 > r5) r3=1 else r3=0, r4++
* r4 += r3, r4++ (jump over one if r2 > r5)
* r4 = 2, r4++ (jump to 2+1, goto D)
* r1 += 1
* if (r1 > r5) r3=1 else r3=0, r4++
* r4 += r3, r4++ (jump over one if r1 > r5)
* r4=1, r4++ (jump to 1+1, goto E)
* r4 *= r4, r4++ [end?]
* A: r5 += 2, r4++
* r5 *= r5 (square), r4++
* r5 *= r4, r4++
* r5 *= 11, r4++
* r3 += 4, r4++
* r3 *= r4, r4++
* r3 += 21, r4++
* r5 += r3, r4++
* r4 += r0, r4++, [r0=1 so goto B:]
* seti 0 5 4
* B: r3 = r1 + r4, r4++
* r3 *= r4, r4++
* r3 += r4, r4++
* r3 *= r4, r4++
* r3 *= 14, r4++
* r3 *= r4, r4++
* r5 += r3, r4++
* r0 = 0, r4++
* r4 = 0, r4++, goto C (top+1)
*/
/*
* goto A, r4=16, r4++ (r4=17 in the end)
* do {
* // First entrance here
* r0 = 0
* r1 = 0
* r2 = 0
* r3 = 10550400
* r4 = 1
* r5 = 10551345
*
* C:
* r1 = 1, r4++
* E:
* r2 = 1, r4++
*
* do {
* r3 = r1 * r2, r4++
* if (r3 != r5) r4 += r3, r4++
* r4 += 1, r4++
* r0 += r1, r4++
* r2 += 1, r4++
* } while(r2 <= r5)
*
* r1 += 1
* if (r1 > r5) r3=1 else r3=0, r4++
* r4 += r3, r4++ (jump over one if r1 > r5)
* r4=1, r4++ (jump to 1+1, goto E)
*
* r4 *= r4, r4++ [end?]
*
* A: r5 += 2, r4++
* r5 *= r5 (square), r4++
* r5 *= r4, r4++
* r5 *= 11, r4++
* r3 += 4, r4++
* r3 *= r4, r4++
* r3 += 21, r4++
* r5 += r3, r4++
* r4 += r0, r4++, [r0=1 so goto B:]
* r4 = 0, r4++
* B: r3 = r1 + r4, r4++
* r3 *= r4, r4++
* r3 += r4, r4++
* r3 *= r4, r4++
* r3 *= 14, r4++
* r3 *= r4, r4++
* r5 += r3, r4++
* r0 = 0, r4++
*
* // At this point (beginning) generated here
* r0 = 0
* r1 = 0
* r2 = 0
* r3 = 10550400
* r4 = 1
* r5 = 10551345
* } while(true)
*/
// The top part seems to be counting how many factors/divisors
// there are from 1 to 10551345 in 10551345, then 2 to 10551345, then 3 to 10551345...
// Each step adds the number of factors there
var max = 10551345;
var divisors = max.GetDivisors();
var ret = 0;
for (int i = 1; i <= max; i++)
{
ret += divisors.Count(v => v >= i);
}
return(ret.ToString());
}