Sync LeetCode submission Runtime - 70 ms (19.87%), Memory - 8.2 MB (1…

…1.26%)

leetcode/0463-island-perimeter/README.md

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+<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>

leetcode/0463-island-perimeter/solution.go

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+func islandPerimeter(grid [][]int) int {
+    n := len(grid)
+    m := len(grid[0])
+    x := 0
+    y := 0
+    vis := make([][]bool, n)
+    for i := range grid {
+        vis[i] = make([]bool, m)
+        for j := range grid[i] {
+            vis[i][j] = false
+        }
+    }
+    for i := range grid {
+        for j := range grid[i] {
+            if grid[i][j] == 1 {
+                x = i
+                y = j
+                break
+            }
+        }
+        if grid[x][y] == 1 {
+            break;
+        }
+    }
+    ret := 0
+    q := []int {x,y}
+    for len(q) != 0 {
+        x := q[0]
+        y := q[1]
+        q = q[2:]
+        if x < 0 || x >= n || y < 0 || y >= m || grid[x][y] == 0 {
+            ret++
+            continue
+        }
+        if vis[x][y] {
+            continue
+        }
+        vis[x][y] = true
+        q = append(q, x+1, y, x-1, y, x, y+1, x, y-1)
+    }
+    return ret
+}