24/7 2×2 #2
Twenty Four Seven 2-by-2 #2
题目详情
Each of the grids above is incomplete. Place numbers in some of the empty cells so that in total each grid’s interior contains one 1, two 2’s, etc., up to seven 7’s. Furthermore, each row and column within each grid must contain exactly 4 numbers which sum to 20. Finally, the numbered cells must form a connected region, but every 2-by-2 subsquare in the completed grid must contain at least one empty cell.
Some numbers have been placed inside each grid. Additionally, some blue numbers have been placed outside of the grids. These blue numbers indicate the first value seen in the corresponding row or column when looking into the grid from that location.
Once each of the grids is complete, create a 7-by-7 grid by “adding” the four grids’ interiors together (as if they were 7-by-7 matrices). The answer to this month’s puzzle is the sum of the squares of the values in this final grid.
解析
Original Explanation
The four completed grids are shown above, and below them is the sum of the corresponding entries, whose sums of squares came to 8520. Below is the list of the successful solvers of the December challenge!