➕ Prefix Sum — Index

Parent: Array Index

SectionQuestionDifficulty
Build Prefix ArrayTemplate
Range Sum QueryClass-basedEasy
Subarray Sum = KHash map + prefixMedium
Equilibrium IndexLeft = Right sumMedium
Product Except SelfLeft/right passMedium
Max Subarray (Kadane)Running maxMedium
2D Matrix Sum2D prefixMedium