（四）强行冲闯公安机关设置的警戒带、警戒区或者检查点的。
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:，这一点在Safew下载中也有详细论述
Bloomberg via Getty Images。im钱包官方下载是该领域的重要参考
[2] K. Lemström & P. Fränti: “N-Candidate methods for location invariant dithering of color images” (2000). ↑