Create 1857-largest-color-value-in-a-directed-graph.kt

Author: a93a

kotlin/1857-largest-color-value-in-a-directed-graph.kt

@@ -0,0 +1,45 @@
+class Solution {
+    fun largestPathValue(colors: String, edges: Array<IntArray>): Int {
+        val adj = HashMap<Int, ArrayList<Int>>()
+        for ((from, to) in edges)
+            adj[from] = adj.getOrDefault(from, ArrayList<Int>()).apply{this.add(to)}
+
+        val visited = HashSet<Int>()
+        val path = HashSet<Int>()
+        val count = Array(colors.length){IntArray(26)}
+
+        fun dfs(node: Int): Int {
+            if (node in path)
+                return Integer.MAX_VALUE
+            if (node in visited)
+                return 0
+            
+            visited.add(node)
+            path.add(node)
+
+            val colorIndex = colors[node] - 'a'
+            count[node][colorIndex] = 1
+
+            adj[node]?.forEach{ nei ->
+                if (dfs(nei) == Integer.MAX_VALUE)
+                    return Integer.MAX_VALUE
+                (0 until 26).forEach{ c ->
+                    count[node][c] = maxOf(
+                        count[node][c],
+                        count[nei][c] + if(c == colorIndex) 1 else 0
+                    )
+                }
+            } 
+
+            path.remove(node)
+            return count[node].max()!!
+        }
+
+        var res = 0
+        for (i in 0 until colors.length) {
+            res = maxOf(res, dfs(i))
+        }
+
+        return if(res == Integer.MAX_VALUE) -1 else res
+    }
+}