Kotlin: 329. Longest Increasing Path in a Matrix

Author: MaratKhakim

kotlin/329-Longest-Increasing-Path-In-A-Matrix.kt

@@ -0,0 +1,41 @@
+class Solution {
+    fun longestIncreasingPath(matrix: Array<IntArray>): Int {
+        val m = matrix.size
+        val n = matrix[0].size
+        val memo = Array<IntArray>(m){IntArray(n)}
+        val dirs = arrayOf(intArrayOf(-1,0),intArrayOf(1,0),intArrayOf(0,1),intArrayOf(0,-1))
+        var res = 1
+
+        for (i in 0..m-1) {
+            for (j in 0..n-1) {
+                val len = dfs(matrix, i, j, dirs, memo)
+                res = Math.max(res, len)
+            }
+        }
+
+        return res
+    }
+
+    fun dfs(matrix: Array<IntArray>, row: Int, col: Int, dirs: Array<IntArray>, memo: Array<IntArray>): Int {
+        val m = matrix.size
+        val n = matrix[0].size
+
+        if (memo[row][col] != 0)
+            return memo[row][col]
+
+        var len = 1
+
+        for (dir in dirs) {
+            val x = dir[0] + row
+            val y = dir[1] + col
+
+            if (x < 0 || x == m || y < 0 || y == n || matrix[row][col] >= matrix[x][y])
+                continue
+
+            len = Math.max(len, 1+dfs(matrix, x, y, dirs, memo))
+        }
+
+        memo[row][col] = len
+        return len
+    }
+}