2022-10-25：在一个 2 * 3 的板上（board）有 5 块砖瓦，用数字 1~5 来表示, 以及一块空缺用 0 来表示。一次 移动 定义为选择 0 与一个相邻的数字（上下左右）进行交换.

use std::collections::HashSet;impl Solution {    pub fn sliding_puzzle(m: Vec<Vec<i32>>) -> i32 {        unsafe {            nexts = vec![0, 0, 0];            let mut set: HashSet<i32> = HashSet::new();            let from =                m[0][0] * b6 + m[0][1] * b5 + m[0][2] * b4 + m[1][0] * b3 + m[1][1] * b2 + m[1][2];            let mut heap = Vec::new();            // [            // 从from出发到达当前状态，已经走了几步，            // 从当前状态到最终状态的估计距离            // 当前状态是什么，用数字代表            // ]            heap.push(vec![0, Solution::distance(from), from]);            let mut ans = -1;            while heap.len() > 0 {                heap.sort_by(|a, b| (b[0] + b[1]).cmp(&(a[0] + a[1])));                let arr = heap.pop().unwrap();                let distance = arr[0];                let cur = arr[2];                if set.contains(&cur) {                    continue;                }                if cur == 123450 {                    ans = distance;                    break;                }                set.insert(cur);                let next_size = Solution::nexts(cur);                for i in 0..next_size {                    let next = nexts[i as usize];                    if !set.contains(&next) {                        heap.push(vec![distance + 1, Solution::distance(next), next]);                    }                }            }            return ans;        }    }
    unsafe fn nexts(from: i32) -> i32 {        // 301245        //  10000        // a = 3        let a = from / b6;        // b = 0        let b = (from / b5) % 10;        // c = 1        let c = (from / b4) % 10;        // d = 2        let d = (from / b3) % 10;        // e = 4        let e = (from / b2) % 10;        // f = 5        let f = from % 10;        if a == 0 {            nexts[0] = from + (b - a) * b6 + (a - b) * b5;            nexts[1] = from + (d - a) * b6 + (a - d) * b3;            return 2;        } else if b == 0 {            nexts[0] = from + (a - b) * b5 + (b - a) * b6;            nexts[1] = from + (c - b) * b5 + (b - c) * b4;            nexts[2] = from + (e - b) * b5 + (b - e) * b2;            return 3;        } else if c == 0 {            nexts[0] = from + (b - c) * b4 + (c - b) * b5;            nexts[1] = from + (f - c) * b4 + (c - f);            return 2;        } else if d == 0 {            nexts[0] = from + (a - d) * b3 + (d - a) * b6;            nexts[1] = from + (e - d) * b3 + (d - e) * b2;            return 2;        } else if e == 0 {            nexts[0] = from + (b - e) * b2 + (e - b) * b5;            nexts[1] = from + (d - e) * b2 + (e - d) * b3;            nexts[2] = from + (f - e) * b2 + (e - f);            return 3;        } else {            nexts[0] = from + (e - f) + (f - e) * b2;            nexts[1] = from + (c - f) + (f - c) * b4;            return 2;        }    }
    // 当前的数，num    // 最终要去的数，123450    // 返回num -> 123450 曼哈顿距离！    fn distance(num: i32) -> i32 {        let a = -1;        let b = i32::abs(a);        let mut ans = end[(num / b6) as usize][0] + end[(num / b6) as usize][1];        ans +=            end[((num / b5) % 10) as usize][0] + i32::abs(end[((num / b5) % 10) as usize][1] - 1);        ans +=            end[((num / b4) % 10) as usize][0] + i32::abs(end[((num / b4) % 10) as usize][1] - 2);        ans +=            i32::abs(end[((num / b3) % 10) as usize][0] - 1) + end[((num / b3) % 10) as usize][1];        ans += i32::abs(end[((num / b2) % 10) as usize][0] - 1)            + i32::abs(end[((num / b2) % 10) as usize][1] - 1);        ans +=            i32::abs(end[(num % 10) as usize][0] - 1) + i32::abs(end[(num % 10) as usize][1] - 2);        return ans;    }}
const b6: i32 = 100000;
const b5: i32 = 10000;
const b4: i32 = 1000;
const b3: i32 = 100;
const b2: i32 = 10;
static mut nexts: Vec<i32> = vec![];
const end: [[i32; 2]; 6] = [[1, 2], [0, 0], [0, 1], [0, 2], [1, 0], [1, 1]];
fn main() {    let nums = vec![vec![1, 2, 3], vec![4, 0, 5]];    let ans = Solution::sliding_puzzle(nums);    println!("ans = {:?}", ans);}
struct Solution {}