diff --git a/E_121_BestTimetoBuyandSellStock.java b/E_121_BestTimetoBuyandSellStock.java
new file mode 100644
index 0000000..c4dd382
--- /dev/null
+++ b/E_121_BestTimetoBuyandSellStock.java
@@ -0,0 +1,21 @@
+class Solution {
+    public int maxProfit(int[] prices) {
+        int min=100000;
+        int max=-1;
+        int diff=0;
+        for(int i: prices){
+            if(i<min){
+                min=i;
+                max=-1;
+            }
+            else if(max<i){
+                max=i;
+                if(max-min>diff){
+                    diff=max-min;
+                }
+
+            }
+        }
+        return diff;
+    }
+}
\ No newline at end of file