Solved 0980

Author: guangsheng.li01

src/a0980_unique_paths_iii.rs

@@ -0,0 +1,83 @@
+/*
+ * [0980] unique-paths-iii
+ */
+
+pub struct Solution {}
+
+// solution impl starts here
+
+impl Solution {
+    pub fn unique_paths_iii(grid: Vec<Vec<i32>>) -> i32 {
+        let mut grid = grid;
+        let (mut x, mut r, mut c) = (1, 0, 0);
+        for ir in 0..grid.len() {
+            let row = &grid[ir];
+            for ic in 0..row.len() {
+                if row[ic] == 0 {
+                    x += 1;
+                } else if row[ic] == 1 {
+                    r = ir as i32;
+                    c = ic as i32;
+                }
+            }
+        }
+
+        Solution::dfs(&mut grid, r, c, x)
+    }
+
+    fn dfs(grid: &mut Vec<Vec<i32>>, r: i32, c: i32, x: i32) -> i32 {
+        if r < 0
+            || c < 0
+            || r >= grid.len() as i32
+            || c >= grid[0].len() as i32
+            || grid[r as usize][c as usize] == -1
+        {
+            return 0;
+        }
+
+        let (ur, uc) = (r as usize, c as usize);
+        if grid[ur][uc] == 2 {
+            return if x == 0 { 1 } else { 0 };
+        }
+
+        grid[ur][uc] = -1;
+        let res = Solution::dfs(grid, r + 1, c, x - 1)
+            + Solution::dfs(grid, r - 1, c, x - 1)
+            + Solution::dfs(grid, r, c + 1, x - 1)
+            + Solution::dfs(grid, r, c - 1, x - 1);
+        grid[ur][uc] = 0;
+        res
+    }
+}
+
+// solution impl ends here
+
+// solution tests starts here
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_case0() {
+        assert_eq!(
+            Solution::unique_paths_iii(vec![vec![1, 0, 0, 0], vec![0, 0, 0, 0], vec![0, 0, 2, -1]]),
+            2
+        );
+    }
+
+    #[test]
+    fn test_case1() {
+        assert_eq!(
+            Solution::unique_paths_iii(vec![vec![1, 0, 0, 0], vec![0, 0, 0, 0], vec![0, 0, 0, 2]]),
+            4
+        );
+    }
+
+    #[test]
+    fn test_case2() {
+        assert_eq!(Solution::unique_paths_iii(vec![vec![0, 1], vec![2, 0]]), 0);
+    }
+}
+
+// solution tests ends here

src/lib.rs

@@ -30,6 +30,7 @@ mod a0931_minimum_falling_path_sum;
 mod a0937_reorder_data_in_log_files;
 mod a0949_largest_time_for_given_digits;
 mod a0973_k_closest_points_to_origin;
+mod a0980_unique_paths_iii;
 mod a1021_remove_outermost_parentheses;
 mod a1047_remove_all_adjacent_duplicates_in_string;
 mod a1200_minimum_absolute_difference;