marcuccio / n-queens-puzzle

The eight queens puzzle is the problem of placing N chess queens on an N×N chessboard so that no two queens threaten each other.

This code is able to solve the n-queens-problem with 10K queens in less than 5s

Build & run

cargo run --release

0	1	2	3
[0;0]	[0;1]	[0;2]	[0;3]
[1;0]	[1;1]	[1;2]	[1;3]
[2;0]	[2;1]	[2;2]	[2;3]
[3;0]	[3;1]	[3;2]	[3;3]

We need 3 vectors to keep in memory all the conflicts and speed up the execution:

• rows[n]
• forw_diags[2n-1]
• backw_diags[2n-1]

What I learned

1. By default the rust test harness hides output from test execution to keep results readable. Test output can be recovered (e.g., for debugging) by passing --nocapture to the test binaries:

   cargo test -- --nocapture

2. How to implement fmt::Display trait in custom struct.