Typorithm · easy

Two Pointers Intro

patternstwo-pointerssorted-array

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Full lesson · 3 learning steps Open any exercise for focused practice

Step 1 of 3 · intro card

Learn Two Pointers

Basic Patterns

Two pointers track two positions and move them based on the current state.

A common version starts one pointer at the left side and one at the right side.

For sorted arrays, pointer movement can discard impossible choices without checking every pair.

The important skill is knowing which pointer should move and why.

Use left and right indexes.

Move one pointer after each comparison.

Sorted input gives movement meaning.

Often improves nested-loop solutions.

let left = 0;
let right = arr.length - 1;

while (left < right) {
  const sum = arr[left] + arr[right];
}

Read the concept map and follow the code breakdown.

Type the implementation, repair mistakes and work through every recall exercise.

Use the final check without hints; revisit weak concepts in short practice sessions.