Update 0200.岛屿数量.深搜版.md about

problems/0200.岛屿数量.深搜版.md

@@ -279,6 +279,42 @@ class Solution:
         return result
 ```
 
+Rust:
+
+
+```rust
+impl Solution {
+    const DIRECTIONS: [(i32, i32); 4] = [(0, 1), (1, 0), (-1, 0), (0, -1)];
+    pub fn num_islands(grid: Vec<Vec<char>>) -> i32 {
+        let mut visited = vec![vec![false; grid[0].len()]; grid.len()];
+        let mut res = 0;
+        for (i, chars) in grid.iter().enumerate() {
+            for (j, &c) in chars.iter().enumerate() {
+                if !visited[i][j] && c == '1' {
+                    res += 1;
+                    Self::dfs(&grid, &mut visited, (i as i32, j as i32));
+                }
+            }
+        }
+        res
+    }
+
+    pub fn dfs(grid: &Vec<Vec<char>>, visited: &mut Vec<Vec<bool>>, (x, y): (i32, i32)) {
+        for (dx, dy) in Self::DIRECTIONS {
+            let (nx, ny) = (x + dx, y + dy);
+            if nx < 0 || nx >= grid.len() as i32 || ny < 0 || ny >= grid[0].len() as i32 {
+                continue;
+            }
+            let (nx, ny) = (nx as usize, ny as usize);
+            if grid[nx][ny] == '1' && !visited[nx][ny] {
+                visited[nx][ny] = true;
+                Self::dfs(grid, visited, (nx as i32, ny as i32));
+            }
+        }
+    }
+}
+```
+
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