<p>You are given <code>row x col</code> <code>grid</code> representing a map where <code>grid[i][j] = 1</code> represents&nbsp;land and <code>grid[i][j] = 0</code> represents water.</p>

<p>Grid cells are connected <strong>horizontally/vertically</strong> (not diagonally). The <code>grid</code> is completely surrounded by water, and there is exactly one island (i.e., one or more connected land cells).</p>

<p>The island doesn&#39;t have &quot;lakes&quot;, meaning the water inside isn&#39;t connected to the water around the island. One cell is a square with side length 1. The grid is rectangular, width and height don&#39;t exceed 100. Determine the perimeter of the island.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img src="https://assets.leetcode.com/uploads/2018/10/12/island.png" style="width: 221px; height: 213px;" />
<pre>
<strong>Input:</strong> grid = [[0,1,0,0],[1,1,1,0],[0,1,0,0],[1,1,0,0]]
<strong>Output:</strong> 16
<strong>Explanation:</strong> The perimeter is the 16 yellow stripes in the image above.
</pre>

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

<pre>
<strong>Input:</strong> grid = [[1]]
<strong>Output:</strong> 4
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> grid = [[1,0]]
<strong>Output:</strong> 4
</pre>

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

<ul>
	<li><code>row == grid.length</code></li>
	<li><code>col == grid[i].length</code></li>
	<li><code>1 &lt;= row, col &lt;= 100</code></li>
	<li><code>grid[i][j]</code> is <code>0</code> or <code>1</code>.</li>
	<li>There is exactly one island in <code>grid</code>.</li>
</ul>

class Solution {
private:
    int directions[4][2] = {{-1,0},{1, 0},{0,-1},{0,1}};
    void dfs(vector<vector<int>>& grid, int i, int j, int &primeter ){
        grid[i][j] = -1;
        for (auto [di, dj]: directions){
            if (i+di<0 || i+di>= grid.size() || j+dj<0 || j+dj>=grid[0].size() || grid[i+di][j+dj]==0)
                primeter++;                
            else if (grid[i+di][j+dj]==1){
                dfs(grid, i+di, dj+j,primeter);
            }
        }
    }
public:
    int islandPerimeter(vector<vector<int>>& grid) {
        int primeter = 0;
        for (int i=0; i<grid.size(); i++){
            for (int j=0; j<grid[0].size(); j++){
                if (grid[i][j] == 1){
                    dfs(grid, i, j, primeter);
                    return primeter;               
                }
            }
        }
        return 0;
    }
};
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