Track 16 · Lesson 8 of 12

Two pointers and sliding windows

Walk through sequences with two indexes instead of nested loops: find pairs in sorted data and compute running windows such as moving averages and longest streaks in O(n).

You will be able to

• Find pairs in sorted data by moving two pointers towards each other
• Compute fixed-size window results by updating a running total instead of re-summing
• Use a variable-size window that grows and shrinks to find the longest valid stretch
• Argue why each technique is O(n): every pointer only moves forward