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use crate::solver::Solver;
use crate::structs::GapHeights;
/// Solve for a given N and return the resulting wall
pub struct NormalSolver<T: num::PrimInt> {
pub n: u32,
/// calculated height [might not be correct!]
pub h: u32,
/// width
pub w: u32,
/// Use to store already used blocks as a bitmask
solve_stack: Vec<SaveState<T>>,
permutations: Vec<Vec<u32>>,
}
// used during row creation, will get deprecated
static mut COUNT: u32 = 0;
static mut TRIES: u32 = 0;
static mut SOLUTIONS: u32 = 0;
/// Save the current state for each row
#[derive(Clone, Copy)]
pub struct SaveState<T: num::PrimInt> {
/// Mask of all currently used stones
pub bitmask: T,
/// sum of all placed stones
pub sum: u32,
/// the row index
pub row: u32,
}
impl<T: num::PrimInt> SaveState<T> {
pub fn new() -> Self {
Self {
bitmask: T::zero(),
sum: 0,
row: unsafe {
COUNT += 1;
COUNT
},
}
}
#[allow(dead_code)]
pub fn set_bit(&mut self, stone: u32) {
self.bitmask =
self.bitmask | T::from(1 << stone).expect("Stone placing index out of bounds");
}
#[allow(dead_code)]
pub fn get_bit(&self, stone: u32) -> T {
self.bitmask & T::from(1 << stone).expect("Requested stone index out of bounds")
}
#[allow(dead_code)]
pub fn bridges_gap(&self, gap: u32) -> bool {
self.get_bit(gap - self.sum) == T::zero()
}
#[allow(dead_code)]
pub fn bridge_gap(mut self, gap: u32) -> Self {
self.set_bit(gap - self.sum);
self.sum = gap;
self
}
}
impl<T: num::PrimInt> NormalSolver<T> {
pub fn new(n: u32) -> Self {
let h = n / 2 + 1;
let w = h * (n - 1);
let mut heap = (1..=n).collect::<Vec<u32>>();
let heap = permutohedron::Heap::new(&mut heap);
let n_f = permutohedron::factorial(n as usize);
let mut permutations = Vec::with_capacity(n_f);
println!("Generating permutations");
for data in heap {
permutations.push(data.clone());
}
Self {
n,
h,
w,
solve_stack: vec![SaveState::new(); h as usize],
permutations,
}
}
pub fn solve(&mut self) {
//for (n, i) in self.permutations.iter().enumerate() {
// println!("perm {}: {:?}", n, i);
//}
println!("calculate results");
self.permute(
permutohedron::factorial(self.n as usize),
0,
((0..self.h).collect::<Vec<u32>>()).as_ref(),
);
unsafe { println!("tries: {}\nsolutions: {}", TRIES, SOLUTIONS) }
}
fn permute(&mut self, up: usize, index: usize, numbers: &[u32]) {
let chunk = self.permutations.len() / self.h as usize;
if index as usize == numbers.len() {
//println!("checking {:?}", numbers);
if self.check_perm(&numbers) {
println!("success");
}
return;
}
let mut new_num = Vec::from(numbers);
for i in numbers[index as usize] as usize..((index + 1) * chunk) {
for n in (index + 1)..numbers.len() {
new_num[n] = (n * chunk) as u32;
}
self.permute(up, index + 1, &new_num);
new_num[index] += 1;
}
}
fn check_perm(&mut self, nums: &[u32]) -> bool {
unsafe {
TRIES += 1;
}
let mut sums = vec![self.w; self.w as usize];
for (i, num) in nums.iter().enumerate() {
let mut sum = 0;
for n in self.permutations[*num as usize][..(self.n - 1 - (self.n & 1)) as usize].iter()
{
sum += *n as usize;
if sums[sum - 1] != self.w {
return false;
}
sums[sum - 1] = i as u32;
}
}
unsafe {
SOLUTIONS += 1;
}
//println!("{:?}", sums);
GapHeights::from_heights(sums.iter().map(|x| *x as u32).collect()).output(self.n, self.h);
//.as_stone_wall(self.n)
//.output();
true
}
#[allow(dead_code)]
fn check_gaps(&mut self, wall: &GapHeights) -> bool {
for (i, r) in wall.iter().enumerate() {
let stone = (i + 1) as u32 - self.solve_stack[r as usize].sum;
self.solve_stack[r as usize].set_bit(stone);
}
for state in self.solve_stack.as_ref() as &[SaveState<T>] {
if state.bitmask != T::from(1 << self.n).unwrap() {
return false;
}
}
true
}
}
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