This puzzle is a Nikoli original.
Puzzle and Goal
An unsolved puzzle consists of a rectangular grid. Some regions have been marked off in gray; some of these contain a number. There are also some number clues in the white area.
The goal is to draw a vertical or horizontal line from each white number clue to a gray area.
The solved grid must satisfy the following conditions:
White number clues indicate the length of their single line (not including the clue).
Lines may not cross each other or white clues, but may cross gray areas.
Each line must end in a gray area.
The clues in gray areas indicate the total length of all lines ending in that area.