nqueens: N queens problem

Description Usage Arguments Details Author(s) References Examples

Description

Solves the N queens problem for any n-by-n board.

Usage

1
2
3

Arguments

n

Size of the chessboard

Details

Uses a direct transcript of Bo Bernhardsson's method.

All solutions (up to reflection and translation) for the 8-by-8 case given in the examples.

Author(s)

Robin K. S. Hankin

References

Examples

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
bernhardsson(7)

a <-
  matrix(
         c(3,6,2,7,1,4,8,5,
           2,6,8,3,1,4,7,5,
           6,3,7,2,4,8,1,5,
           3,6,8,2,4,1,7,5,
           4,8,1,3,6,2,7,5,
           7,2,6,3,1,4,8,5,
           2,6,1,7,4,8,3,5,
           1,6,8,3,7,4,2,5,
           1,5,8,6,3,7,2,4,
           2,4,6,8,3,1,7,5,
           6,3,1,8,4,2,7,5,
           4,6,8,2,7,1,3,5)
         ,8,12)

out <- array(0L,c(8,8,12))
for(i in 1:12){
  out[cbind(seq_len(8),a[,i],i)] <- 1L
}

magic documentation built on Jan. 26, 2018, 5:03 p.m.