Create 0341-flatten-nested-list-iterator.java

Author: sujal-goswami

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

@@ -0,0 +1,27 @@
+public class NestedIterator implements Iterator<Integer> {
+    Queue<NestedInteger> q; // here we use Queue in place of revesed stack
+
+    public NestedIterator(List<NestedInteger> nestedList) {
+        q = new LinkedList<>();
+        dfs(nestedList);
+    }
+
+    @Override
+    public Integer next() {
+        return q.poll().getInteger();
+    }
+
+    @Override
+    public boolean hasNext() {
+        return !q.isEmpty();
+    }
+
+    private void dfs(List<NestedInteger> nestedList){
+        for(NestedInteger n : nestedList){
+            if(n.isInteger())
+                q.add(n);
+            else
+                dfs(n.getList());    
+        }
+    }
+}