Two Repeating Elements
Negates visited array index values as markers to detect recurring elements in-place.
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 two_repeating(arr):
repeating = []
for x in arr:
idx = abs(x)
if arr[idx] < 0: repeating.append(idx)
else: arr[idx] = -arr[idx]
return repeatingEmbed this visualization
Drop a live, looping Two Repeating Elements canvas into a blog post or course page.
<iframe src="/embed/two-repeating-elements" 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 Two Repeating Elements?
Two Repeating Elements runs in O(n) time and O(1) auxiliary space.
Is the Two Repeating Elements 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 Two Repeating Elements in interviews?
Two Repeating Elements shows up in interviews at Uber, Microsoft, DoorDash.
How does the 3D visualization of Two Repeating Elements 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.