From 5183eb0cd19f91aa0260b428b97a71fedc702142 Mon Sep 17 00:00:00 2001
From: Ashwagandha-coder <max.cacz@yandex.ru>
Date: Sun, 1 Jun 2025 15:57:24 +0100
Subject: [PATCH 1/2] add 341

---
 .../github/contest/design/DesignLeetcode.kt   | 42 +++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/contest/src/main/java/com/github/contest/design/DesignLeetcode.kt b/contest/src/main/java/com/github/contest/design/DesignLeetcode.kt
index cf8cc40..2145960 100644
--- a/contest/src/main/java/com/github/contest/design/DesignLeetcode.kt
+++ b/contest/src/main/java/com/github/contest/design/DesignLeetcode.kt
@@ -245,4 +245,46 @@ class CombinationIterator(characters: String, combinationLength: Int) {
         combine(index + 1, str, subset, store, limit)
     }
 
+}
+
+/**
+ * 341. Flatten Nested List Iterator
+ */
+
+class NestedInteger {
+    fun getInteger(): Int? {
+        return null
+    }
+
+    fun getList(): List<NestedInteger>? {
+        return null
+    }
+}
+
+class NestedIterator(nestedList: List<NestedInteger>) {
+
+    private val store = mutableListOf<Int>()
+
+    init {
+        nestedList.forEach {
+            dfs(it)
+        }
+    }
+
+    private fun dfs(obj: NestedInteger) {
+        val action = obj.getInteger()
+        if (action != null) {
+            store.add(action)
+            return
+        }
+
+        obj.getList()?.forEach {
+            dfs(it)
+        }
+    }
+
+
+    fun next(): Int = store.removeFirst()
+
+    fun hasNext(): Boolean = store.isNotEmpty()
 }
\ No newline at end of file

From 661f4d7c7ee51ebcd0ebbd6aa4c57470ed5c4857 Mon Sep 17 00:00:00 2001
From: Ashwagandha-coder <max.cacz@yandex.ru>
Date: Sun, 1 Jun 2025 16:39:19 +0100
Subject: [PATCH 2/2] add 341

---
 .../design/DesignAlternativeSolution.kt       | 29 +++++++++++++++++++
 .../github/contest/design/DesignLeetcode.kt   |  3 ++
 2 files changed, 32 insertions(+)
 create mode 100644 contest/src/main/java/com/github/contest/design/DesignAlternativeSolution.kt

diff --git a/contest/src/main/java/com/github/contest/design/DesignAlternativeSolution.kt b/contest/src/main/java/com/github/contest/design/DesignAlternativeSolution.kt
new file mode 100644
index 0000000..05a2edc
--- /dev/null
+++ b/contest/src/main/java/com/github/contest/design/DesignAlternativeSolution.kt
@@ -0,0 +1,29 @@
+package com.github.contest.design
+
+/**
+ * 341. Flatten Nested List Iterator
+ * Alternative Solution
+ */
+
+class NestedIteratorAlternativeSolution(nestedList: List<NestedInteger>) {
+
+    private val stack = ArrayDeque<NestedInteger>().apply {
+        nestedList.reversed().forEach { addFirst(it) }
+    }
+
+    fun next(): Int {
+        if (!hasNext()) throw NoSuchElementException()
+        return stack.removeFirst().getInteger()!!
+    }
+
+    fun hasNext(): Boolean {
+        while (stack.isNotEmpty()) {
+            val top = stack.first()
+            if (top.isInteger()) {
+                return true
+            }
+            stack.removeFirst().getList()?.reversed()?.forEach { stack.addFirst(it) }
+        }
+        return false
+    }
+}
\ No newline at end of file
diff --git a/contest/src/main/java/com/github/contest/design/DesignLeetcode.kt b/contest/src/main/java/com/github/contest/design/DesignLeetcode.kt
index 2145960..2239dd1 100644
--- a/contest/src/main/java/com/github/contest/design/DesignLeetcode.kt
+++ b/contest/src/main/java/com/github/contest/design/DesignLeetcode.kt
@@ -252,6 +252,9 @@ class CombinationIterator(characters: String, combinationLength: Int) {
  */
 
 class NestedInteger {
+
+    fun isInteger() = true
+
     fun getInteger(): Int? {
         return null
     }