from [1 2 3 4 5] take 2 numbers, find all combinations:

go run combination.go

• [1 2]
• [1 3]
• [1 4]
• [1 5]
• [2 3]
• [2 4]
• [2 5]
• [3 4]
• [3 5]
• [4 5]

There is a 12L barrel full of gasoline, and there is a 9L barrel and a 5L barrel, how to divide the 12L gasoline into two parts?

go run split.go

• 12 0 0
• 3 9 0
• 3 4 5
• 7 0 5
• 7 5 0
• 2 5 5
• 2 9 1
• 11 0 1
• 11 1 0
• 6 1 5
• 6 6 0