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|
use super::Puzzle;
use rand::Rng;
impl Puzzle {
/// O(N)
pub fn max_queen_col(&mut self) -> usize {
let (mut max_attack, mut max_queens) = (i32::MIN, Vec::new());
for col in 0..self.N {
let attacks = self.attacks(col, self.in_col[col]);
if attacks > max_attack {
max_attack = attacks;
max_queens.clear();
}
if attacks == max_attack {
max_queens.push(col);
}
}
if max_queens.len() > 1 {
return max_queens[self.rng.gen_range(0..max_queens.len())];
}
return max_queens[0];
}
/// O(N)
pub fn min_col_row(&mut self, colI: usize) -> usize {
let (mut min_row, mut min_ind) = (i32::MAX, Vec::new());
for row in 0..self.N {
let attacks = self.attacks(colI, row);
if attacks < min_row {
min_row = attacks;
min_ind.clear();
}
if attacks == min_row {
min_ind.push(row);
}
}
if min_ind.len() > 1 {
return min_ind[self.rng.gen_range(0..min_ind.len())];
}
return min_ind[0];
}
/// O(1)
pub fn update(&mut self, colI: usize, val: i32) {
assert!(colI < self.N && (val == 1 || val == -1), "Bad arguments to update: {} {}!", colI, val);
self.per_row[self.in_col[colI]] += val;
self.per_d1[colI + self.N - 1 - self.in_col[colI]] += val;
self.per_d2[colI + self.in_col[colI]] += val;
if val < 0 {
// Sanity check when removing a queen
self.in_col[colI] = self.N;
}
}
/// O(1)
pub fn move_queen(&mut self, colI: usize, rowI: usize) {
if rowI == self.in_col[colI] { return; }
self.update(colI, -1);
self.in_col[colI] = rowI;
self.update(colI, 1);
}
}
#[test]
fn test_max_queen_col() {
let mut e1 = Puzzle::example1();
assert_eq!(e1.max_queen_col(), 2, "Bad max_queen_col on single max!");
let mut e2 = Puzzle::example2();
let mut got = [false; 4];
for _ in 0..10000 {
got[e2.max_queen_col()] = true;
}
assert!(got.iter().all(|&x| x), "Bad max_queen_col on multiple max!");
}
#[test]
fn test_min_col_row() {
let mut e1 = Puzzle::example1();
let mut got = [false; 4];
for _ in 0..10000 {
got[e1.min_col_row(0)] = true;
}
assert!(got[0] && !got[1] && got[2] && got[3], "Bad min_col_row on multiple (3) min!");
got = [false; 4];
for _ in 0..10000 {
got[e1.min_col_row(2)] = true;
}
assert!(got[0] && !got[1] && got[2] && !got[3], "Bad min_col_row on multiple (2) min!");
let mut e2 = Puzzle::example2();
assert_eq!(e2.min_col_row(0), 3, "Bad min_col_row on single min!");
assert_eq!(e2.min_col_row(3), 1, "Bad min_col_row on single min!");
}
#[test]
fn test_update() {
let mut e1 = Puzzle::example1();
e1.update(0, -1);
e1.update(2, -1);
e1.in_col[0] = 3;
e1.update(0, 1);
e1.in_col[2] = 1;
e1.update(2, 1);
let e1s = Puzzle::example1();
assert_eq!(e1, e1s, "Bad update!");
}
#[test]
fn test_move_queen() {
let e1s = Puzzle::example1();
let mut e1 = Puzzle::example1();
e1.move_queen(0, 0);
e1.move_queen(0, 3);
assert_eq!(e1, e1s, "Bad move_queen identity!");
let mut e1 = Puzzle::example1();
e1.move_queen(2, 0);
e1.move_queen(2, 1);
assert_eq!(e1, e1s, "Bad move_queen identity on moved max!");
let mut e1 = Puzzle::example1();
e1.move_queen(0, 0);
e1.move_queen(2, 2);
let e2 = Puzzle::example2();
assert_eq!(e1, e2, "Bad move_queen on changed maxes!");
}
|
