Create Next Smaller Left.java

Author: py3-coder

Stack_Interview Problem/Next Smaller Left.java

@@ -0,0 +1,28 @@
+https://practice.geeksforgeeks.org/problems/help-classmates--141631/1?utm_source=gfg&utm_medium=article&utm_campaign=bottom_sticky_on_article
+
+class Solution{
+    static List<Integer> leftSmaller(int n, int arr[])
+    {
+        //Lets Play with Stack::
+        List<Integer> res = new ArrayList<>();
+        Stack<Integer> st = new Stack<>();
+        for(int i=0;i<n;i++){
+            if(st.isEmpty()){
+                res.add(-1);
+            }else if(st.peek()<arr[i]){
+                res.add(st.peek());
+            }else{
+                while(!st.isEmpty() && st.peek()>=arr[i]){
+                    st.pop();
+                }
+                if(st.isEmpty()){
+                    res.add(-1);
+                }else{
+                    res.add(st.peek());
+                }
+            }
+            st.push(arr[i]);
+        }
+        return res;
+    }
+}