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Fixed Points and Strike Mandates

Many tasks in compilation and program analysis (in symbolic computation in general, I suppose) amount to finding solutions to systems of the form \(x = f(x)\). However, when asked to define algorithms to find such fixed points, we rarely stop and ask “which fixed point are we looking for?” In practice, we tend to be interested in fixed points of monotone functions: given a partial order \((\prec)\), we have \(a \prec b \Rightarrow...

codercareer

No. 34 - String Path in Matrix

Question: How to implement a function to check whether there is a path for a string in a matrix of characters?  It moves to left, right, up and down in a matrix, and a cell for a movement. The path can start from any entry in a matrix. If a cell is occupied by a character of a string on the path, it cannot be occupied by another character again.For example, the matrix below with three rows and four columns has a path for the string...

blog.thecodewhisperer.com blog.thecodewhisperer.com

10 Ways to Kill Your Design

I wish that I could take credit for this article, but I can’t. Instead, I have to credit two people: Lasse Koskela and Miško Hevery. I credit Lasse for writing the manuscript that led me to Miško’s article. Look for Lasse’s upcoming book Unit Testing in Java at Manning Publications’ site. Let me summarize Miško’s article here, then you can read the details at his blog. Why would I simply summarize someone else’s article...