<p>On an <code>2 x 3</code> board, there are five tiles labeled from <code>1</code> to <code>5</code>, and an empty square represented by <code>0</code>. A <strong>move</strong> consists of choosing <code>0</code> and a 4-directionally adjacent number and swapping it.</p>

<p>The state of the board is solved if and only if the board is <code>[[1,2,3],[4,5,0]]</code>.</p>

<p>Given the puzzle board <code>board</code>, return <em>the least number of moves required so that the state of the board is solved</em>. If it is impossible for the state of the board to be solved, return <code>-1</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/06/29/slide1-grid.jpg" style="width: 244px; height: 165px;" />
<pre>
<strong>Input:</strong> board = [[1,2,3],[4,0,5]]
<strong>Output:</strong> 1
<strong>Explanation:</strong> Swap the 0 and the 5 in one move.
</pre>

<p><strong class="example">Example 2:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/06/29/slide2-grid.jpg" style="width: 244px; height: 165px;" />
<pre>
<strong>Input:</strong> board = [[1,2,3],[5,4,0]]
<strong>Output:</strong> -1
<strong>Explanation:</strong> No number of moves will make the board solved.
</pre>

<p><strong class="example">Example 3:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2021/06/29/slide3-grid.jpg" style="width: 244px; height: 165px;" />
<pre>
<strong>Input:</strong> board = [[4,1,2],[5,0,3]]
<strong>Output:</strong> 5
<strong>Explanation:</strong> 5 is the smallest number of moves that solves the board.
An example path:
After move 0: [[4,1,2],[5,0,3]]
After move 1: [[4,1,2],[0,5,3]]
After move 2: [[0,1,2],[4,5,3]]
After move 3: [[1,0,2],[4,5,3]]
After move 4: [[1,2,0],[4,5,3]]
After move 5: [[1,2,3],[4,5,0]]
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>board.length == 2</code></li>
	<li><code>board[i].length == 3</code></li>
	<li><code>0 &lt;= board[i][j] &lt;= 5</code></li>
	<li>Each value <code>board[i][j]</code> is <strong>unique</strong>.</li>
</ul>

class Solution {
public:
    int slidingPuzzle(vector<vector<int>>& board) {
        string ss="";
        unordered_map<string,int> mp;
        queue<pair<pair<int,int>,string>> q;
        ss = to_string(board[0][0])+to_string(board[0][1])+to_string(board[0][2])+to_string(board[1][0])+to_string(board[1][1])+to_string(board[1][2]);
        mp[ss] = 1;
        int steps=0;
        for(int i=0;i<2;i++){
            for(int j=0;j<3;j++){
                if(board[i][j]==0){
                    q.push({{i,j},ss});
                    break;
                }
            }
        }
        while(!q.empty()){
            int sz = q.size();
            for(int i=0;i<sz;i++){
                int x = q.front().first.first;
                int y = q.front().first.second;
                string s = q.front().second;
                if(s=="102453") cout<<x<<" "<<y<<endl;
                q.pop();
                if(s=="123450") return steps;
                if(x+1<2){
                    swap(s[y+3],s[y]);
                    if(mp[s]==0){
                        q.push({{x+1,y},s});
                        mp[s] = 1;
                    }
                    swap(s[y+3],s[y]);
                }
                if(x-1>=0){
                    swap(s[y],s[y+3]);
                    if(mp[s]==0){
                        q.push({{x-1,y},s});
                        mp[s] = 1;
                    }
                    swap(s[y+3],s[y]);
                }
                if(y+1<3){
                    if(x==0){
                        swap(s[y],s[y+1]);
                        if(s=="120453") cout<<"*"<<endl;
                        if(mp[s]==0){
                            q.push({{x,y+1},s});
                            mp[s] = 1;
                        }
                        swap(s[y+1],s[y]);
                    }
                    else{
                        swap(s[y+3],s[y+4]);
                        if(mp[s]==0){
                            q.push({{x,y+1},s});
                            mp[s] = 1;
                        }
                        swap(s[y+3],s[y+4]);
                    }
                }
                if(y-1>=0){
                    if(x==0){
                        swap(s[y],s[y-1]);
                        if(mp[s]==0){
                            q.push({{x,y-1},s});
                            mp[s] = 1;
                        }
                        swap(s[y-1],s[y]);
                    }
                    else{
                        swap(s[y+3],s[y+2]);
                        if(mp[s]==0){
                            q.push({{x,y-1},s});
                            mp[s] = 1;
                        }
                        swap(s[y+3],s[y+2]);
                    }
                }
            }
            steps++;
        }
        return -1;
    }
};
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