Current my project euler status.

Solving problems ordered is sometimes very boring.  So I am solving recent problems as possible.  Solving 3-digit problems is not easy to me.  The maximum difficulty level is 70% currently.  Generally, solving greater than 50% is comsume 2 or 3 days.  Sometimes, I gave up.

Almost problems I made my own solutions.  But 2 or 3 problems, I cannot find solution.  For example problem #78.  My best solution is this.

f(n, n) = f(n, n-1) + 1
f(n, 1) = 1
f(n, r) = f(n, r-1) + f(n-r, r)

Using above fire equation, I found the answer exceeded 40,000.  Due to memory allocation limitation, I cannot allocate more array.  I can solve this problem after search wikipedia. T.T