Search Insert Position

Binary search · Search for the first valid position · Easy · about 18 min

Why it matters

Boundary search is the foundation for harder “search the answer” problems.

How it connects

Binary search is not only exact matching: it can find the boundary where a rule becomes true.

Try first

At the end of a failed search, what does left point to?

Interview cue

I preserve the insertion invariant, so the final left boundary is the answer.