chore: add some comments to the algorithm of dropinfo adjustment by t…

…imes

internal/util/reportverifs/verify_drops.go

@@ -125,20 +125,26 @@ func (d *DropVerifier) adjustDropInfosByTimes(itemDropInfos []*model.DropInfo, t
 
 	for _, dropInfo := range itemDropInfos {
 		dropTypeItemTypeCountMap[dropInfo.DropType] += 1
+		// for item drop info, we need to adjust multiple the original bounds by times
 		dropInfo.Bounds.Lower *= times
 		dropInfo.Bounds.Upper *= times
 		if dropInfo.Bounds.Exceptions != nil {
+			// Adjusting exceptions by times will make the range very complicated, so we just remove it
 			dropInfo.Bounds.Exceptions = nil
 		}
 	}
 
 	for _, dropInfo := range typeDropInfos {
-		min := times
-		if dropTypeItemTypeCountMap[dropInfo.DropType] < min {
-			min = dropTypeItemTypeCountMap[dropInfo.DropType]
+		// The lower bound remains the same, because no matter how many times you play, you can always get at least as many types as the lower bound
+		// For upper bound, if times < item_type_count_for_this_drop_type, it means it's impossible to get each type at least once, so we adjust upper bound to be max(oldUpper, times)
+		// if times > item_type_count_for_this_drop_type, it means you are able to get each type at lease once, so we adjust upper bound to be max(oldUpper, item_type_count_for_this_drop_type)
+		// newUpper = max(oldUpper, min(times, item_type_count_for_this_drop_type))
+		minBetweenTimesAndItemTypeCount := times
+		if dropTypeItemTypeCountMap[dropInfo.DropType] < minBetweenTimesAndItemTypeCount {
+			minBetweenTimesAndItemTypeCount = dropTypeItemTypeCountMap[dropInfo.DropType]
 		}
-		if min > dropInfo.Bounds.Upper {
-			dropInfo.Bounds.Upper = min
+		if minBetweenTimesAndItemTypeCount > dropInfo.Bounds.Upper {
+			dropInfo.Bounds.Upper = minBetweenTimesAndItemTypeCount
 		}
 		if dropInfo.Bounds.Exceptions != nil {
 			dropInfo.Bounds.Exceptions = nil