private int GetCollatzSequenceBruteForce(CollatzChain chain)
{
if (chain.CurrentNumber == 1)
{
return(chain.Length);
}
Solve(chain);
return(GetCollatzSequenceBruteForce(chain));
}
private void GetCollatzSequenceMemoized(CollatzChain chain)
{
if (_cache.ContainsKey(chain.CurrentNumber))
{
chain.Length += _cache[chain.CurrentNumber];
}
else if (chain.CurrentNumber != 1)
{
Solve(chain);
GetCollatzSequenceMemoized(chain);
}
}
private static long Calculate(int limit, List <int> chainLengths, Func <CollatzChain, int> calc)
{
var watch = System.Diagnostics.Stopwatch.StartNew();
for (int ii = 1; ii <= limit; ii++)
{
var chain = new CollatzChain(ii);
chainLengths.Add(calc(chain));
}
watch.Stop();
var memoizedPerformance = watch.ElapsedMilliseconds;
return(memoizedPerformance);
}
public override int SolveCollatzBruteForce(CollatzChain chain)
{
while (true)
{
if (chain.CurrentNumber != 1)
{
Solve(chain);
}
else
{
break;
}
}
return(chain.Length);
}
// Here is an example of solving the problem while using memoization. In every loop
// we first check if the local cache has the collatz chain length stored for the
// current number. If it does, we use the precomputed value for our calculation
// instead of recalculating it all over again. If the chain length isn't stored,
// we simply continue on with the algorithm as normal.
public override int SolveCollatzMemoized(CollatzChain chain)
{
while (true)
{
if (_cache.ContainsKey(chain.CurrentNumber))
{
chain.Length += _cache[chain.CurrentNumber];
break;
}
else if (chain.CurrentNumber != 1)
{
Solve(chain);
}
else
{
break;
}
}
_cache.Add(chain.NumToCalculate, chain.Length);
return(chain.Length);
}
public override int SolveCollatzMemoized(CollatzChain chain)
{
GetCollatzSequenceMemoized(chain);
_cache.Add(chain.NumToCalculate, chain.Length);
return(chain.Length);
}
public override int SolveCollatzBruteForce(CollatzChain chain)
{
return(GetCollatzSequenceBruteForce(chain));
}
