Survo puzzles: www.survo.fi/puzzles
---------------------------------------
Copyright (c) Survo Systems 2006-2016

The easiest way to solve these three problems may be
using a Javascript application
http://www.survo.fi/javascript/SurvoPuzzle.html
based on the swapping method.

Survo puzzle 375/2016 (40) #443-20048

   A  B  C  D
1  *  *  8  * 40
2 10  *  *  * 21
3  * 13  *  5 42
4  *  *  *  * 33
  55 43 26 12

Survo puzzle 376/2016 (120) #443-35754

   A  B  C  D
1  *  * 11  * 33
2  9  *  *  * 44
3  *  *  * 10 20
4  *  4  *  * 39
  24 14 43 55

Survo puzzle 377/2016 (355) #443-40790

   A  B  C  D
1  *  *  *  * 37
2  *  *  *  * 49
3  *  *  7  * 21
4  *  *  *  * 29
  15 54 42 25