Two Sum (sorted)
Too small, move left up. Too big, move right down. The sorted order makes that safe.
Decision · step 2 of 5Two Pointers: Two sum on a sorted array
1 + 15 = 16, too big. Only a smaller right value can help, so right moves down.
What you will see
The sum label updates; exactly one pointer moves per step.
Cost
| Best | O(1) |
|---|---|
| Average | O(n) |
| Worst | O(n) |
| Space | O(1) |
How you work with it here
play it through, step one change at a time, scrub to any step, run it on your own input, predict what happens next.
Screen readers: Pointers announce their name and index; each step announces which pointer moved and why.
Reduced motion: Pointers appear at their new index with a brief emphasis instead of gliding.
Before this
Related
Taught by the same lesson
Two Pointers covers these too, in the same run.