diff --git a/src/main/java/com/cool/ling_cha_mount/stack/Num901.java b/src/main/java/com/cool/ling_cha_mount/stack/Num901.java
new file mode 100644
index 0000000..3a06b39
--- /dev/null
+++ b/src/main/java/com/cool/ling_cha_mount/stack/Num901.java
@@ -0,0 +1,46 @@
+package com.cool.ling_cha_mount.stack;
+
+import java.util.ArrayList;
+import java.util.Deque;
+import java.util.LinkedList;
+import java.util.List;
+
+public class Num901 {
+
+}
+class StockSpanner {
+
+    Deque<Integer> stack=new LinkedList<>();
+    List<Integer> list=new ArrayList<>();
+    public StockSpanner() {
+        stack.push(-1);
+    }
+
+    public int next(int price) {
+        list.add(price);
+        while(stack.peek()>0&&list.get(stack.peek())<=price){
+            stack.pop();
+        }
+        int res=list.size()-1-stack.peek();
+        stack.push(list.size()-1);
+        return res;
+    }
+}
+class StockSpanner1 {
+
+    Deque<int[]> stack = new LinkedList<>();
+    private int curDay = -1;
+
+    public StockSpanner1() {
+        stack.push(new int[] { curDay, Integer.MAX_VALUE });
+    }
+
+    public int next(int price) {
+        while (price >= stack.peek()[1]) {
+            stack.pop();
+        }
+        int res = (++curDay) - stack.peek()[0];
+        stack.push(new int[] { curDay, price });
+        return res;
+    }
+}