Sync LeetCode submission Runtime - 3 ms (80.99%), Memory - 7.7 MB (9.…

…93%)

leetcode/0200-number-of-islands/README.md

@@ -0,0 +1,38 @@
+<p>Given an <code>m x n</code> 2D binary grid <code>grid</code> which represents a map of <code>&#39;1&#39;</code>s (land) and <code>&#39;0&#39;</code>s (water), return <em>the number of islands</em>.</p>
+
+<p>An <strong>island</strong> is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the grid are all surrounded by water.</p>
+
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<pre>
+<strong>Input:</strong> grid = [
+  [&quot;1&quot;,&quot;1&quot;,&quot;1&quot;,&quot;1&quot;,&quot;0&quot;],
+  [&quot;1&quot;,&quot;1&quot;,&quot;0&quot;,&quot;1&quot;,&quot;0&quot;],
+  [&quot;1&quot;,&quot;1&quot;,&quot;0&quot;,&quot;0&quot;,&quot;0&quot;],
+  [&quot;0&quot;,&quot;0&quot;,&quot;0&quot;,&quot;0&quot;,&quot;0&quot;]
+]
+<strong>Output:</strong> 1
+</pre>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<pre>
+<strong>Input:</strong> grid = [
+  [&quot;1&quot;,&quot;1&quot;,&quot;0&quot;,&quot;0&quot;,&quot;0&quot;],
+  [&quot;1&quot;,&quot;1&quot;,&quot;0&quot;,&quot;0&quot;,&quot;0&quot;],
+  [&quot;0&quot;,&quot;0&quot;,&quot;1&quot;,&quot;0&quot;,&quot;0&quot;],
+  [&quot;0&quot;,&quot;0&quot;,&quot;0&quot;,&quot;1&quot;,&quot;1&quot;]
+]
+<strong>Output:</strong> 3
+</pre>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>m == grid.length</code></li>
+	<li><code>n == grid[i].length</code></li>
+	<li><code>1 &lt;= m, n &lt;= 300</code></li>
+	<li><code>grid[i][j]</code> is <code>&#39;0&#39;</code> or <code>&#39;1&#39;</code>.</li>
+</ul>

leetcode/0200-number-of-islands/solution.go

@@ -0,0 +1,29 @@
+func numIslands(grid [][]byte) int {
+    n := len(grid)
+    m := len(grid[0])
+    vis := make([][]bool, n)
+    for i := range vis {
+        vis[i] = make([]bool, m)
+    }
+    ret := 0
+    for i := range grid {
+        for j := range grid[i] {
+            if vis[i][j] || grid[i][j] == '0' {
+                continue
+            }
+            ret++
+            q := []int {i,j}
+            for len(q) >= 2 {
+                x := q[0]
+                y := q[1]
+                q = q[2:]
+                if x < 0 || x >= n || y < 0 || y >= m || vis[x][y] || grid[x][y] == '0'{
+                    continue
+                }
+                vis[x][y] = true
+                q = append(q, x-1, y, x+1, y, x, y-1, x, y+1)
+            }
+        }
+    }
+    return ret
+}