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Variables, loops, functions and conditionals
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500 original challenges. Pick an index card and give it a go.
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Variables, loops, functions and conditionals
Variables and expressions
Conditionals
Loop accumulators
State in a loop
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Arrays and strings
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Nested array traversal
String scanning
Maps, sets, counting and sorting
Frequency maps
Set membership
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Map grouping
Comparator sorting
Two pointers, windows and prefix sums
Opposite-end pointers
Read and write pointers
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Variable sliding windows
Prefix range subtraction
Two sorted streams
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Recursion, sorting, binary search and bits
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Linked lists, binary trees and search trees
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Greedy choices, dynamic programming and backtracking
Greedy interval selection
Counting dynamic programming
Unbounded dynamic programming
Zero-one knapsack
Sequence DP with binary search
Interval dynamic programming
Backtracking choices
Backtracking with occupancy
Scheduling DP and binary search
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Title A–Z
Difficulty
STATUS
PROBLEM
DIFFICULTY
TOPIC
Receipt arithmetic: Proof strip
Level 0 · Variables and expressions
Easy
Variables, loops, functions and conditionals
Variables and expressions
Receipt arithmetic: Total receipt
Level 0 · Variables and expressions
Easy
Variables, loops, functions and conditionals
Variables and expressions
Receipt arithmetic: Threshold file
Level 0 · Variables and expressions
Easy
Variables, loops, functions and conditionals
Variables and expressions
Receipt arithmetic: First qualifying slip
Level 0 · Variables and expressions
Easy
Variables, loops, functions and conditionals
Variables and expressions
Receipt arithmetic: Peak ticket
Level 0 · Variables and expressions
Easy
Variables, loops, functions and conditionals
Variables and expressions
Receipt arithmetic: Boss receipt
Level 0 · Variables and expressions
Easy
Variables, loops, functions and conditionals
Variables and expressions
Stamp gates: Proof strip
Level 0 · Conditionals
Easy
Variables, loops, functions and conditionals
Conditionals
Stamp gates: Total receipt
Level 0 · Conditionals
Easy
Variables, loops, functions and conditionals
Conditionals
Stamp gates: Threshold file
Level 0 · Conditionals
Easy
Variables, loops, functions and conditionals
Conditionals
Stamp gates: First qualifying slip
Level 0 · Conditionals
Easy
Variables, loops, functions and conditionals
Conditionals
Stamp gates: Peak ticket
Level 0 · Conditionals
Easy
Variables, loops, functions and conditionals
Conditionals
Stamp gates: Boss receipt
Level 0 · Conditionals
Easy
Variables, loops, functions and conditionals
Conditionals
Ribbon totals: Proof strip
Level 0 · Loop accumulators
Easy
Variables, loops, functions and conditionals
Loop accumulators
Ribbon totals: Total receipt
Level 0 · Loop accumulators
Easy
Variables, loops, functions and conditionals
Loop accumulators
Ribbon totals: Threshold file
Level 0 · Loop accumulators
Easy
Variables, loops, functions and conditionals
Loop accumulators
Ribbon totals: First qualifying slip
Level 0 · Loop accumulators
Easy
Variables, loops, functions and conditionals
Loop accumulators
Ribbon totals: Peak ticket
Level 0 · Loop accumulators
Easy
Variables, loops, functions and conditionals
Loop accumulators
Ribbon totals: Boss receipt
Level 0 · Loop accumulators
Easy
Variables, loops, functions and conditionals
Loop accumulators
Reset tallies: Proof strip
Level 0 · State in a loop
Easy
Variables, loops, functions and conditionals
State in a loop
Reset tallies: Total receipt
Level 0 · State in a loop
Easy
Variables, loops, functions and conditionals
State in a loop
Reset tallies: Threshold file
Level 0 · State in a loop
Easy
Variables, loops, functions and conditionals
State in a loop
Reset tallies: First qualifying slip
Level 0 · State in a loop
Easy
Variables, loops, functions and conditionals
State in a loop
Reset tallies: Peak ticket
Level 0 · State in a loop
Easy
Variables, loops, functions and conditionals
State in a loop
Reset tallies: Boss receipt
Level 0 · State in a loop
Easy
Variables, loops, functions and conditionals
State in a loop
Digit workshop: Proof strip
Level 0 · Helper functions
Easy
Variables, loops, functions and conditionals
Helper functions
Digit workshop: Total receipt
Level 0 · Helper functions
Easy
Variables, loops, functions and conditionals
Helper functions
Digit workshop: Threshold file
Level 0 · Helper functions
Easy
Variables, loops, functions and conditionals
Helper functions
Digit workshop: First qualifying slip
Level 0 · Helper functions
Easy
Variables, loops, functions and conditionals
Helper functions
Digit workshop: Peak ticket
Level 0 · Helper functions
Easy
Variables, loops, functions and conditionals
Helper functions
Digit workshop: Boss receipt
Level 0 · Helper functions
Easy
Variables, loops, functions and conditionals
Helper functions
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