Merge pull request neetcode-gh#2701 from kousukekikuchi1984/feature/l…

…ongest-increasing-path-in-a-matrix

Create 0329-longest-increasing-path-in-a-matrix.rs

rust/0329-longest-increasing-path-in-a-matrix.rs

@@ -0,0 +1,43 @@
+impl Solution {
+ pub fn longest_increasing_path(matrix: Vec<Vec<i32>>) -> i32 {
+ use std::cmp::max;
+ use std::collections::HashMap;
+
+ let mut dp: HashMap::<(usize, usize), i32> = HashMap::new();
+
+ fn dfs(
+ r: usize,
+ c: usize,
+ prevVal: i32,
+ matrix: &[Vec<i32>],
+ dp: &mut HashMap<(usize, usize), i32>,
+ ) -> i32 {
+ if r < 0
+ || r >= matrix.len()
+ || c < 0
+ || c >= matrix[0].len()
+ || matrix[r][c] <= prevVal
+ {
+ return 0;
+ }
+ if let Some(&result) = dp.get(&(r, c)) {
+ return result;
+ }
+
+ let mut res = 1;
+ res = max(res, 1 + dfs(r + 1, c, matrix[r][c], matrix, dp));
+ res = max(res, 1 + dfs(r - 1, c, matrix[r][c], matrix, dp));
+ res = max(res, 1 + dfs(r, c + 1, matrix[r][c], matrix, dp));
+ res = max(res, 1 + dfs(r, c - 1, matrix[r][c], matrix, dp));
+ dp.insert((r, c), res);
+ res
+ }
+
+ for r in 0..matrix.len() {
+ for c in 0..matrix[0].len() {
+ dfs(r, c, -1, &matrix, &mut dp);
+ }
+ }
+ *dp.values().max().unwrap_or(&1)
+ }
+}