create 0200-number-of-islands.rs

rust/0200-number-of-islands.rs

@@ -0,0 +1,36 @@
+impl Solution {
+ pub fn num_islands(grid: Vec<Vec<char>>) -> i32 {
+ fn dfs(grid: &mut Vec<Vec<char>>, x: i32, y: i32) {
+ if x < 0
+ || y < 0
+ || x >= grid.len() as i32
+ || y >= grid[0].len() as i32
+ || grid[x as usize][y as usize] == '0'
+ {
+ return;
+ }
+
+ grid[x as usize][y as usize] = '0';
+
+ let directions: [(i32, i32); 4] = [(0, 1), (1, 0), (0, -1), (-1, 0)];
+
+ for (add_x, add_y) in directions {
+ dfs(grid, x + add_x, y + add_y);
+ }
+ }
+
+ let mut count = 0;
+ let mut new_grid = grid.clone();
+
+ for x in 0..grid.len() {
+ for y in 0..grid[0].len() {
+ if new_grid[x][y] == '1' {
+ count += 1;
+ dfs(&mut new_grid, x as i32, y as i32);
+ }
+ }
+ }
+
+ count
+ }
+}