The first step, is to stop allocating "memory", and start allocating specific somethings else. Consider the usage pattern:
I learned that for 4-SAT, if clause to variable ratio is more than 10, the generated problems become difficult to solve, and the likelihood of formula to be SAT or UNSAT is close to 50%. So I generated 3 types of formulas:
。关于这个话题，爱思助手下载最新版本提供了深入分析
The expanding hex-based world map contains lots for players to discover
The 'magical' blue flower changing farmers' fortunes in India