Update 0695.岛屿的最大面积.md about rust

problems/0695.岛屿的最大面积.md

@@ -439,6 +439,51 @@ impl Solution {
 }
 ```
 
+dfs: 版本二
+
+```rust
+impl Solution {
+    const DIRECTIONS: [(i32, i32); 4] = [(0, 1), (1, 0), (-1, 0), (0, -1)];
+
+    pub fn max_area_of_island(grid: Vec<Vec<i32>>) -> i32 {
+        let mut visited = vec![vec![false; grid[0].len()]; grid.len()];
+
+        let mut res = 0;
+        for (i, nums) in grid.iter().enumerate() {
+            for (j, &num) in nums.iter().enumerate() {
+                if !visited[i][j] && num == 1 {
+                    let mut count = 0;
+                    Self::dfs(&grid, &mut visited, (i as i32, j as i32), &mut count);
+                    res = res.max(count);
+                }
+            }
+        }
+
+        res
+    }
+
+    pub fn dfs(
+        grid: &Vec<Vec<i32>>,
+        visited: &mut [Vec<bool>],
+        (x, y): (i32, i32),
+        count: &mut i32,
+    ) {
+        if visited[x as usize][y as usize] || grid[x as usize][y as usize] == 0 {
+            return;
+        }
+        visited[x as usize][y as usize] = true;
+        *count += 1;
+        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;
+            }
+            Self::dfs(grid, visited, (nx, ny), count);
+        }
+    }
+}
+```
+
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