# NQueens Solver
## Find one solution in O(1)
```rust
#[test]
fn find_solution() {
for i in 0..=8 {
match NQueens::solve(i) {
None => println!("Rank {} has no solution", i),
Some(s) => println!("\n{}", s),
}
}
}
```
## Find first 4 solution of rank 5
```rust
#[test]
fn find_partial() {
for (i, s) in NQueens::solve_all(5).enumerate().take(4) {
println!("Solution #{}:", i + 1);
println!("{}", s);
}
}
```
## Find next solution by lexicographical order
```rust
#[test]
fn find_next() {
let s1 = NQueens::solve(5).unwrap();
let s2 = NQueens::solve_next(s1).unwrap();
println!("Solution #2:");
println!("{}", s2);
}
```