Sudoku Companion Lite

This program will be your companion when playing sudoku. It's also a solver willing to explain when needed.
Landscape and portrait modes are accepted, and the display is similar on all types of devices.
This is a limited version. An unlimited payed-for version is available.

100 puzzles grouped in 4 different levels of difficulty are present.
Play with or without visible candidates (pencil marks).
The Companion is able to give hints and explain applicable techniques.
The history is two ways unlimited do / redo with mark / return to mark.
The exploration of all techniques applicable for a given puzzle is completed in some seconds.
Saving current session (with its history) lets you alternate playing several grids.

★★ The puzzles ★★
The internal puzzles are ordered by increasing difficulty.
The following techniques may be needed
• easy: unique (singleton), hidden unique
• medium: blocked (bloc - line or block - column interaction), hidden blocked, nude pairs, nude triplets
• hard: hidden pairs, hidden triplets, x-wing, swordfish, xy-wing, xyz-wing, xy-chaine
• very hard: nice loop

★★ Import export ★★
The manual editor lets you import a personal puzzel.
To export, do a long tap on the grid and choose one of the "copy" options.

★★ Saving a session ★★
On program closing the current session is registered to be reloaded next time.
To save a session at any moment while playing, do a long tap on the grid and choose "save session".
When the saved sessions are displayed, a long tap on an item lets you delete the session.
Saving a session is a means to store puzzles imported by edition.