Time: 221 ms (35%), Space: 40.5 MB (40%) - LeetHub

Author: hajin-kim

0341-flatten-nested-list-iterator/0341-flatten-nested-list-iterator.kt

@@ -0,0 +1,20 @@
+class NestedIterator(nestedList: List<NestedInteger>) {
+    private val flat: List<Int> = nestedList.flatten()
+    private val iterator = flat.iterator()
+
+    private fun List<NestedInteger>.flatten(): List<Int> =
+        flatMap {
+            if (it.isInteger())
+                listOf(it.getInteger()!!)
+            else
+                it.getList()!!.flatten()
+        }
+
+    fun next(): Int {
+        return iterator.next()
+    }
+
+    fun hasNext(): Boolean {
+        return iterator.hasNext()
+    }
+}