2018-12 在职刷题保持状态， 每天1题+ML insights

Day61

Solved  226

Solved  227 Reverse Polish Notation

Solved  232

Day62

Solved 241

Solved 246

Solved 247

Day63

Solved 258

Solved 250

Solved 249

Day64

Solved 829. Just a math problem.
Solved 713 with two pt

Solved 263

Have to debug a serious issue today at work. Fight on!

Day65

Solved 642 with Trie
Solved 648
Solved 649 greedy.

Day66

Solved 670

Solved 639 with DP. Recursion+mem might TLE.
Solved 772. Cleaning up the expression before hand saves tremendous work.

Reverse Polish notation generation handling of operators: pop the op in stack if the incoming rank is not bigger than the op in the stack.

Day67

Solved 637

Solved 299

Solved 394

Day68

Solved 426

Solved 268

Solved 99

Day69

Solved 525

Solved 572

Solved 314

Day70

Solved 523

Solved 554
Solved 489

Finally root caused a very low-level bug related to MMX instruction and FPU registers.

ML Reviewed:

DNN

Weight initialization (Xavier method to render the variance to 1/n, n is the input dimension, help gradient explosion/diminishing)
regularization (l1,l2,dropout, early stopping)

Planned review of optimization today.

ML Reviewed:

Momentum, RMSProp, Adam. Bias corrections.
Batch norm (affine function of normalized Z, which helps alleviate covariate shift. Note that need to have the estimates of mu and sigma in order to apply batch norm during test time)