Merge pull request neetcode-gh#2701 from kousukekikuchi1984/feature/longest-increasing-path-in-a-matrix

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

Author: tahsintunan

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)
+    }
+}