Interactive DSA and system design

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8stepsO(n)averageO(1)space

Techniques lab

Two Pointer Converging Sum

Step 1 / 8

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← R

Comparing Pivot / Mid Swapping Sorted / Found Active Range

Animation speed

Space play / pause←→ stepR reset

Current operation

Start

Find two numbers in the sorted array that sum to 100. Place one pointer at the start and one at the end, then converge.

Algorithm state

100Target Sumidx 0 = 8Left →idx 9 = 96← Right

Try your own input

Use 3-12 positive numbers separated by commas.

Complexity notes

O(n)averageO(n)worstO(1)spaceN/Astable

Synced code trace

function twoPointer(arr, target) {  let left = 0, right = arr.length - 1;  while (left < right) {    const sum = arr[left] + arr[right];    if (sum === target) return [left, right];    else if (sum < target) left++;    else right--;  }  return null;}

Interactive Notes

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