completed assignment

force-app/main/default/triggers/DiscountOpportunity.trigger

@@ -0,0 +1,31 @@
+trigger DiscountOpportunity on Opportunity (before insert,before update) {
+        Map<Decimal, Decimal> discountTiers = new Map<Decimal, Decimal> 
+        {
+        100000 => 0.10, 
+        50000 => 0.05 
+    };
+
+    Decimal maxDiscount = 20000;
+
+    for (Opportunity opportunity : Trigger.New)
+    {
+        Decimal discountAmount = 0;
+
+        for (Decimal tierAmount : discountTiers.keySet())
+        {
+            if (opportunity.Amount >= tierAmount)
+            {
+                discountAmount = opportunity.Amount * discountTiers.get(tierAmount);
+                break;
+            }
+        }
+
+        if (discountAmount > maxDiscount) {
+            opportunity.Discount_Amount__c.addError('Maximum discount exceeded!');
+        } else {
+            
+            opportunity.Discount_Amount__c = discountAmount;
+        }
+    }
+
+}