Solution for Evil Sudoku #2181326579441

7
1
8
3
9
8
9
2
6
8
2
1
1
4
5
9
1
6
4
9
8
9
2
3
6
7
5

This Sudoku Puzzle has 71 steps and it is solved using Naked Single, Full House, Hidden Single, Locked Candidates Type 1 (Pointing), Locked Candidates Type 2 (Claiming), Naked Triple, Hidden Pair, undefined, AIC, Locked Pair, Continuous Nice Loop, Skyscraper, Sue de Coq techniques.

Try To Solve This Puzzle

Solution Steps:

  1. Row 5 / Column 3 → 3 (Naked Single)
  2. Row 5 / Column 7 → 7 (Naked Single)
  3. Row 5 / Column 8 → 2 (Naked Single)
  4. Row 5 / Column 2 → 9 (Full House)
  5. Row 3 / Column 1 → 9 (Hidden Single)
  6. Row 6 / Column 4 → 9 (Hidden Single)
  7. Row 9 / Column 9 → 9 (Hidden Single)
  8. Row 9 / Column 8 → 8 (Hidden Single)
  9. Locked Candidates Type 1 (Pointing): 3 in b1 => r2c79<>3
  10. Locked Candidates Type 1 (Pointing): 8 in b6 => r6c6<>8
  11. Locked Candidates Type 1 (Pointing): 1 in b9 => r8c16<>1
  12. Locked Candidates Type 2 (Claiming): 4 in r9 => r7c12,r8c13<>4
  13. Naked Triple: 4,6,7 in r368c6 => r27c6<>4, r2c6<>6, r24c6<>7
  14. Hidden Pair: 1,2 in r1c5,r2c6 => r1c5<>5, r1c5<>6
  15. 2-String Kite: 4 in r3c6,r7c9 (connected by r7c4,r8c6) => r3c9<>4
  16. Locked Candidates Type 2 (Claiming): 4 in r3 => r2c4<>4
  17. XY-Wing: 5/7/4 in r4c3,r69c2 => r9c3<>4
  18. Row 9 / Column 3 → 6 (Naked Single)
  19. XY-Chain: 4 4- r2c7 -1- r2c6 -2- r1c5 -1- r9c5 -7- r9c2 -4 => r2c2<>4
  20. AIC: 4 4- r2c7 -1- r2c6 =1= r7c6 =8= r7c4 =4= r7c9 -4 => r12c9,r8c7<>4
  21. Locked Pair: 1,3 in r8c78 => r78c9,r8c1<>3
  22. Continuous Nice Loop: 4/5/6/7 3= r2c1 =6= r2c4 -6- r8c4 =6= r8c6 -6- r6c6 -7- r6c2 =7= r9c2 =4= r9c1 =1= r7c1 =3= r2c1 =6 => r2c1<>4, r27c1<>5, r3c46<>6, r6c5,r9c1<>7
  23. Skyscraper: 7 in r6c6,r9c5 (connected by r69c2) => r4c5,r8c6<>7
  24. X-Wing: 7 r48 c14 => r23c4<>7
  25. Row 2 / Column 9 → 7 (Hidden Single)
  26. Sue de Coq: r78c4 - {45678} (r23c4 - {456}, r7c6,r9c5 - {178}) => r7c5<>1
  27. Row 7 / Column 5 → 5 (Naked Single)
  28. XY-Chain: 2 2- r1c5 -1- r9c5 -7- r9c2 -4- r9c1 -1- r7c1 -3- r7c2 -2 => r1c2<>2
  29. Row 1 / Column 5 → 2 (Hidden Single)
  30. Row 2 / Column 6 → 1 (Naked Single)
  31. Row 4 / Column 5 → 3 (Naked Single)
  32. Row 2 / Column 7 → 4 (Naked Single)
  33. Row 7 / Column 6 → 8 (Naked Single)
  34. Row 4 / Column 8 → 5 (Naked Single)
  35. Row 6 / Column 5 → 6 (Naked Single)
  36. Row 4 / Column 6 → 2 (Naked Single)
  37. Row 7 / Column 4 → 4 (Naked Single)
  38. Row 4 / Column 3 → 4 (Naked Single)
  39. Row 3 / Column 5 → 7 (Naked Single)
  40. Row 9 / Column 5 → 1 (Full House)
  41. Row 6 / Column 6 → 7 (Naked Single)
  42. Row 4 / Column 4 → 8 (Full House)
  43. Row 4 / Column 1 → 7 (Full House)
  44. Row 6 / Column 2 → 5 (Full House)
  45. Row 3 / Column 4 → 5 (Naked Single)
  46. Row 7 / Column 9 → 2 (Naked Single)
  47. Row 8 / Column 6 → 6 (Naked Single)
  48. Row 3 / Column 6 → 4 (Full House)
  49. Row 2 / Column 4 → 6 (Full House)
  50. Row 8 / Column 4 → 7 (Full House)
  51. Row 9 / Column 1 → 4 (Naked Single)
  52. Row 9 / Column 2 → 7 (Full House)
  53. Row 8 / Column 1 → 5 (Naked Single)
  54. Row 1 / Column 2 → 4 (Naked Single)
  55. Row 3 / Column 9 → 3 (Naked Single)
  56. Row 3 / Column 8 → 6 (Full House)
  57. Row 7 / Column 2 → 3 (Naked Single)
  58. Row 2 / Column 2 → 2 (Full House)
  59. Row 7 / Column 1 → 1 (Full House)
  60. Row 8 / Column 3 → 2 (Full House)
  61. Row 2 / Column 3 → 5 (Full House)
  62. Row 2 / Column 1 → 3 (Full House)
  63. Row 1 / Column 1 → 6 (Full House)
  64. Row 8 / Column 9 → 4 (Naked Single)
  65. Row 6 / Column 9 → 8 (Naked Single)
  66. Row 1 / Column 9 → 5 (Full House)
  67. Row 6 / Column 7 → 3 (Full House)
  68. Row 1 / Column 8 → 1 (Naked Single)
  69. Row 1 / Column 7 → 8 (Full House)
  70. Row 8 / Column 7 → 1 (Full House)
  71. Row 8 / Column 8 → 3 (Full House)
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