[copy title]:
Write an algorithm to determine if a number is "happy".
A happy number is a number defined by the following process: Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not include 1. Those numbers for which this process ends in 1 are happy numbers.
Example: 19 is a happy number
- 12 + 92 = 82
- 82 + 22 = 68
- 62 + 82 = 100
- 12 + 02 + 02 = 1
[brute force solution]:
Time analysis:
Space Analysis:
[Optimized]:
Time analysis:
Space Analysis:
[Wonderful output conditions]:
[Wonderful corner case]:
[Thinking question]:
[One sentence idea]:
[Input amount]: Empty: Normal situation: Extra large: Extra small: Special situations handled in the program: Abnormal situations (Illegal and unreasonable input):
[Paint]:
[One brush]:
[Second brush]:
[Three brushes]:
[Four brushes]:
[Five brushes]:
[Results of five-minute naked eye debug]:
[Summarize]:
[Complexity]: Time complexity: O( ) Space complexity: O( )
[English data structures or algorithms, why not use other data structures or algorithms]:
[Key templating code]:
[Other solutions]:
［Follow Up］：
[The topics given by LC change and change]:
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