Duplicate Number (1 to n)
Floyd's Tortoise and Hare cycle detection in array-as-linked-list.
Live loop — open the studio to scrub, add your own array, or race it in Battle Arena.
Asked in interviews at
Reference implementation (Python)
def find_duplicate(arr):
slow = fast = arr[0]
while True:
slow = arr[slow]
fast = arr[arr[fast]]
if slow == fast: break
slow = arr[0]
while slow != fast:
slow = arr[slow]; fast = arr[fast]
return slowEmbed this visualization
Drop a live, looping Duplicate Number (1 to n) canvas into a blog post or course page.
<iframe src="/embed/duplicate-number-1-to-n" width="100%" height="380" style="border:1px solid #e6e8ec;border-radius:14px" loading="lazy" title="3D algorithm visualization by CodeWithMunnaX"></iframe>Frequently asked
What is the time and space complexity of Duplicate Number (1 to n)?
Duplicate Number (1 to n) runs in O(n) time and O(1) auxiliary space.
Is the Duplicate Number (1 to n) visualizer free?
The core 3D visualizer, Web Audio chimes and step intuition are free. A one-time ₹49 Pro Pass unlocks advanced algorithms, large custom arrays, Battle Arena and reel export.
Which companies ask Duplicate Number (1 to n) in interviews?
Duplicate Number (1 to n) shows up in interviews at Netflix, Amazon, ByteDance.
How does the 3D visualization of Duplicate Number (1 to n) work?
Each array value becomes a 3D pillar whose height maps to its value. Comparisons glow amber, swaps flash red, and settled elements lock green while a floating pointer badge tracks the active index — synchronized line-by-line with the Python code.