## How to Revert Git Commit Remote

First, There are serveral revert situation: Local:

Remote

.

## Happy Number and Prime

A happy number is 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, while those that do not end in 1 are unhappy numbers (or sad numbers).

More formally, given a number , define a sequence , , … where is the sum of the squares of the digits of . Then n is happy if and only if there exists i such that . If a number is happy, then all members of its sequence are happy; if a number is unhappy, all members of the sequence are unhappy. For example, 19 is happy, as the associated sequence is: 12 + 92 = 82 82 + 22 = 68 62 + 82 = 100 12 + 02 + 02 = 1. The happy numbers below 500 are: 1, 7, 10, 13, 19, 23, 28, 31, 32, 44, 49, 68, 70, 79, 82, 86, 91, 94, 97, 100, 103, 109, 129, 130, 133, 139, 167, 176, 188, 190, 192, 193, 203, 208, 219, 226, 230, 236, 239, 262, 263, 280, 291, 293, 301, 302, 310, 313, 319, 320, 326, 329, 331, 338, 356, 362, 365, 367, 368, 376, 379, 383, 386, 391, 392, 397, 404, 409, 440, 446, 464, 469, 478, 487, 490, 496

calculation:

and we can also embed to String

## Triangle Problem

Starting at the top of the triangle below and moving to adjacent numbers on the row below, the maximum total from top to bottom is 23.

```   3
7 4
2 4 6
8 5 9 3

That is, 3 + 7 + 4 + 9 = 23.
```

Find the maximum total from top to bottom of the triangle below: …–

## Learn by Practice Extend and Include

Here is some examples to help understand extend and include

So class have singleton_methods, that should live in the meta_class and that method should be a instance method there extend just put test method to meta class. then later one will cover the first one

result