feat(graphs): add 695_max_area_of_island.rs

Author: whisperpine

README.md

@@ -152,3 +152,4 @@ so that you can use `just tf TEST` command to test.
 | Problem | Difficulty | Solution |
 | - | - | - |
 | 200. Number of Islands | Medium | [200_number_of_islands.rs](./tests/200_number_of_islands.rs) |
+| 695. Max Area of Island | Medium | [695_max_area_of_island.rs](./tests/695_max_area_of_island.rs) |

tests/695_max_area_of_island.rs

@@ -0,0 +1,45 @@
+// 695. Max Area of Island
+// https://leetcode.com/problems/max-area-of-island/description/
+// Topics: Graphs.
+// Difficulty: Medium.
+
+#[test]
+fn test_() {}
+
+#[derive(Debug)]
+pub struct Solution;
+
+// ---------------------------------
+// copy to leetcode starts from here
+// ---------------------------------
+
+impl Solution {
+    pub fn max_area_of_island(mut grid: Vec<Vec<i32>>) -> i32 {
+        let mut max_area: i32 = 0;
+        for x in 0..grid.len() {
+            for y in 0..grid[0].len() {
+                if grid[x][y] == 1 {
+                    max_area = max_area.max(find(&mut grid, x, y));
+                }
+            }
+        }
+        max_area
+    }
+}
+
+fn find(grid: &mut [Vec<i32>], x: usize, y: usize) -> i32 {
+    if x >= grid.len() || y >= grid[0].len() {
+        return 0;
+    }
+    if grid[x][y] != 1 {
+        return 0;
+    }
+    grid[x][y] = 0;
+
+    let v1 = find(grid, x + 1, y);
+    let v2 = find(grid, x, y + 1);
+    let v3 = find(grid, x.wrapping_sub(1), y);
+    let v4 = find(grid, x, y.wrapping_sub(1));
+
+    v1 + v2 + v3 + v4 + 1
+}