<p>In an&nbsp;<code>n*n</code>&nbsp;grid, there is a snake that spans 2 cells and starts moving from the top left corner at <code>(0, 0)</code> and <code>(0, 1)</code>. The grid has empty cells represented by zeros and blocked cells represented by ones. The snake wants to reach the lower right corner at&nbsp;<code>(n-1, n-2)</code>&nbsp;and&nbsp;<code>(n-1, n-1)</code>.</p>

<p>In one move the snake can:</p>

<ul>
	<li>Move one cell to the right&nbsp;if there are no blocked cells there. This move keeps the horizontal/vertical position of the snake as it is.</li>
	<li>Move down one cell&nbsp;if there are no blocked cells there. This move keeps the horizontal/vertical position of the snake as it is.</li>
	<li>Rotate clockwise if it&#39;s in a horizontal position and the two cells under it are both empty. In that case the snake moves from&nbsp;<code>(r, c)</code>&nbsp;and&nbsp;<code>(r, c+1)</code>&nbsp;to&nbsp;<code>(r, c)</code>&nbsp;and&nbsp;<code>(r+1, c)</code>.<br />
	<img alt="" src="https://assets.leetcode.com/uploads/2019/09/24/image-2.png" style="width: 300px; height: 134px;" /></li>
	<li>Rotate counterclockwise&nbsp;if it&#39;s in a vertical position and the two cells to its right are both empty. In that case the snake moves from&nbsp;<code>(r, c)</code>&nbsp;and&nbsp;<code>(r+1, c)</code>&nbsp;to&nbsp;<code>(r, c)</code>&nbsp;and&nbsp;<code>(r, c+1)</code>.<br />
	<img alt="" src="https://assets.leetcode.com/uploads/2019/09/24/image-1.png" style="width: 300px; height: 121px;" /></li>
</ul>

<p>Return the minimum number of moves to reach the target.</p>

<p>If there is no way to reach the target, return&nbsp;<code>-1</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<p><strong><img alt="" src="https://assets.leetcode.com/uploads/2019/09/24/image.png" style="width: 400px; height: 439px;" /></strong></p>

<pre>
<strong>Input:</strong> grid = [[0,0,0,0,0,1],
               [1,1,0,0,1,0],
&nbsp;              [0,0,0,0,1,1],
&nbsp;              [0,0,1,0,1,0],
&nbsp;              [0,1,1,0,0,0],
&nbsp;              [0,1,1,0,0,0]]
<strong>Output:</strong> 11
<strong>Explanation:
</strong>One possible solution is [right, right, rotate clockwise, right, down, down, down, down, rotate counterclockwise, right, down].
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> grid = [[0,0,1,1,1,1],
&nbsp;              [0,0,0,0,1,1],
&nbsp;              [1,1,0,0,0,1],
&nbsp;              [1,1,1,0,0,1],
&nbsp;              [1,1,1,0,0,1],
&nbsp;              [1,1,1,0,0,0]]
<strong>Output:</strong> 9
</pre>

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

<ul>
	<li><code>2 &lt;= n &lt;= 100</code></li>
	<li><code>0 &lt;= grid[i][j] &lt;= 1</code></li>
	<li>It is guaranteed that the snake starts at empty cells.</li>
</ul>

class Solution {
public:
    int dp[101][101][2][2];
    int help(int i1,int j1,int h,int r,vector<vector<int>>& grid){
        int n = grid.size();
        if(i1 == n-1 and j1 == n-1 and h == 1)return 0;
        int ans = 1e6+7;
        if(dp[i1][j1][h][r]!=-1)return dp[i1][j1][h][r];
        if(h==1){
            if(j1+1<n and grid[i1][j1+1] == 0){
                // cout<<i1<<j1<<" ";
                ans = min(ans,1+help(i1,j1+1,h,0,grid));
            }
            if(i1+1<n and grid[i1+1][j1] == 0 and grid[i1+1][j1-1] == 0){
            // cout<<i1<<j1<<" ";
                ans = min(ans,1+help(i1+1,j1,h,0,grid));
            }
        }
        if(h == 0){
            if(j1+1<n and grid[i1][j1+1] == 0 and grid[i1-1][j1+1] == 0){
                ans = min(ans,1+help(i1,j1+1,h,0,grid));
            }
            if(i1+1<n and grid[i1+1][j1] == 0){
            // cout<<i1<<j1<<" ";
                ans = min(ans,1+help(i1+1,j1,h,0,grid));
            }
        }
        if((h == 1) and (r == 0) and i1+1<n and grid[i1+1][j1] == 0 and grid[i1+1][j1-1] == 0){
            // cout<<i1<<j1<<" ";
            // cout<<h<<" ";
            ans = min(ans,1+help(i1+1,j1-1,0,1,grid));
        }
        if((h == 0) and (r == 0) and j1+1<n and grid[i1][j1+1] == 0 and grid[i1-1][j1+1] == 0){
            // cout<<i1<<j1<<" ";
            // cout<<h<<" ";
            ans = min(ans,1+help(i1-1,j1+1,1,1,grid));
        }
        return dp[i1][j1][h][r] = ans;

    }
    int minimumMoves(vector<vector<int>>& grid) {
        memset(dp,-1,sizeof(dp));
        int ans = help(0,1,1,0,grid);
        int n = grid.size();
        if(ans == 1e6 + 7)return -1;
        return ans;
    }
};
14700