Volume CVI (10600-10699)

•  10610 - Gopher and Hawks

•  10611 - The Playboy Chimp

•  10642 - Can You Solve It?

•  10650 - Determinate Prime

•  10689 - Yet another Number...

4

1 4 5 7 // the height always increasing order

query

4

4 6 8 1

For 4: nearest left value 1, and nearest right value 5. Output: 1 5

For 6: nearest left value 5, and nearest right value 7. Output: 5 7

For 8: nearest left value 7, and have not nearest right value. Output: 7 X

For 1: have not nearest left value, and nearest right value 4. Output: X 4

You can find the nearest left value and nearest right value using binary search.

Or you can use c++ stl lower_bound() and upper_bound() method.