ABC Skyscrapers Sudoku (Daily Sudoku League #150)

A few days back I completed 150th Sudoku in the Fun With Sudoku Series. Today I am posting 150th Sudoku in Daily Sudoku League. It was December 2013 when I started posting weekly puzzles in this series with Repeated Neighbours Sudoku. It took almost two years to complete 150 puzzles in this series. Currently, I am posting only once weekly. There was a time when I used to post twice a week for this series. Anyway, it is fun creating the Sudoku puzzle and now I am looking forward to completing my 200th Sudoku in this series.

This Series has a mix of Sudoku variations with Medium to Hard difficulty-level puzzles. Today's puzzle I created long back, but has been kept for a special occasion. So today I am posting this ABC Skyscrapers Sudoku to celebrate my 150th Sudoku in The League of Extraordinary Ladies & Gentlemen. This is my second Sudoku of this type. The previous one was published with the title ABC Skyscrapers Sudoku (Daily Sudoku League #131).

Instructions of ABC Skyscrapers Sudoku

Fill in the grid with letters A, B, C, D, E, and digits 1, 2, 3, and 4 so that each row, column, and outlined 3x3 region contains different symbols. Each number inside the grid represents the height of a building. The number clues outside of the grid indicate how many buildings can be seen when looking from that direction. Taller buildings block the view of smaller buildings, but letters do not affect visibility. Letters outside the grid indicate the first seen letters from the corresponding direction.