[Anagrams] Reduce memory cost

By changing `map<string, string>` to `map<string, int>` to reduce memory cost.
add mine codes for leetcode.
no twisted mathematical hack
amend the explanation of the second solution
add some explaination
new problem's solution
some useful scripts
remove copyright.sh
Merge branch 'patch-1' of https://github.com/jakwings/leetcode into jakwings-patch
Merge branch 'patch-4' of https://github.com/jakwings/leetcode into jakwings-patch
add some comments
Merge branch 'patch-3' of https://github.com/jakwings/leetcode into jakwings-patch
add some comments
Merge branch 'jakwings-patch'
fix the integer overflow issue
fix the INT_MIN definition issue
Binary Tree Upside Down
Add explaination for "Single Number I/II"
Add comments to explain the solutions
Update pascalTriangle.II.cpp

At first, the vector doesn't have element at rowIndex.