Problems › Topics › Prefix sums

Prefix sums practice problems

pattern9 problems

Carry the running total so any span is one subtraction away. A pattern: a move you make, and the kind of thing an interview is really asking you to spot. 9 problems in the bank train it, each with a worked example, a hint and a reference solution.

Start a Prefix sums session →

• Math
• Strings
• Arrays
• Hash maps
• Sorting
• Parsing
• Two pointers
• Sliding window
• Prefix sums
• Stacks
• Binary search
• Intervals
• Grids
• Greedy
• Recursion
• Simulation
• Bit manipulation

9 problems

• Running balance down a statementeasy
• The highest so fareasy
• The day the account went undereasy
• The average so far, after every readingeasy
• How many stretches add up to the figurehard
• Parcel discount bandmedium
• The imbalance across a splitmedium
• Answer a stack of range totalsmedium
• Where the ledger balancesmedium