Happy Number
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What is Happy Number?
A happy number is one that eventually reaches 1 when you repeatedly replace it with the sum of the squares of its digits. Detect whether a number is happy. This is a cycle detection problem: if the process loops without reaching 1, the number is not happy. You can use Floyd's algorithm or a set to detect the cycle. This problem teaches you to recognize cycle detection in non-graph contexts.
Free resources to learn Happy Number
More in stage 21: Math & Geometry
Happy Number: common questions
Can I learn Happy Number in Hindi?
This lesson is written in English. Once you sign in, open it in the interactive course and ask the AI tutor to explain Happy Number in Hindi or Hinglish. The tutor answers from this lesson’s own text, so it stays on the syllabus, and it runs on your own Google, OpenAI or Anthropic key.
Is this Happy Number tutorial for beginners?
It is lesson 135 of 137 in the free LeetCode roadmap, in stage 21, Math & Geometry. If you are new to LeetCode, start from stage 1 and come back here in order; if you already know the earlier stages, this lesson stands on its own.