basically follow the concept: https://luckytoilet.wordpress.com/2012/12/23/2125/

stage1: Uncover the neighbor tiles of "zero" tile first

stage2: Uncover/Flag the easy boundary tiles (can be easly inferred by one edge tile)

stage3: Do edge tiles segmentation and caculate all the configurations. Check if have any 100% safe or 100% mine neighbor tile

stage4: Make the best guess by the probability of mine

current performance

• easy: 832/1000
• medium: 792/1000
• expert: 296/1000

after considering unexplored area

• easy: 874/1000
• medium: 847/1000
• expert: 431/1000

What 's next to do:

• edge tile segmentation (the optimization mentioned in the link above)
• close game strategy (mentioned in the link above)
• hueristic function (?)