Small steps. Stronger solutions.

Your problem-solving journey, one idea at a time.

Season 2027
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A little code. A big beginning.C++23
// One value at a time
int sum = 0;
for (int x : values) {
    sum += x;
}
30
11
42
13
54
sum00/5 values

Your learning path

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Level 0 Training

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Session 01

Programming foundations

Turn a problem statement into a working C++23 program. Learn input, data types, safe arithmetic, decisions, loops, and the habits that make a solution correct.

12 lessonsReady when you are
Session 02

Arrays & strings

Store and revisit values, work with rows and columns, and treat text as a sequence of characters. Build safe scans, searches, transformations, and small state machines.

12 lessonsReady when you are
Session 03

Functions & complexity

Build reusable C++ helpers, make their contracts explicit, and count time and memory before the input gets large.

12 lessonsReady when you are
Session 04

STL: sequences & adaptors

Learn vector, pair, deque, queue, priority_queue, and stack through state changes, ordering rules, and the cost of each operation.

12 lessonsReady when you are
Session 05

Sets & maps

Choose between distinct keys, repeated items, key–value records, and dynamic ranks. Trace the state, make safe updates, and count the real cost.

12 lessonsReady when you are
Session 06

Static range queries

Build prefix totals, count bounded values, and record range additions at their boundaries. Extend the same reasoning to substrings, grids, and layered queries.

12 lessonsReady when you are
From a problem to a programIdentify the input, output, and constraints, then translate a small plan into C++.Variables, types, and remembered valuesChoose a representation, initialize it, and understand what assignment really changes.Arithmetic without surprisesPredict division and remainder, widen before multiplication, and format decimal answers.Conditions and logical decisionsBuild exclusive categories, combine comparisons, and protect operations with short-circuit logic.Optional: other ways to chooseRecognize switch for exact choices and the conditional operator for choosing a value.For loops: make repetition preciseTrace initialization, condition, body, and update—and avoid an extra iteration.While, do-while, and stopping rulesChoose a loop from its stopping condition and read the exact input format.Break, continue, and early answersDistinguish leaving a loop from skipping one iteration, without losing required input.Five patterns worth understandingUse sums, counts, best-so-far candidates, products, and flags to process a stream.Nested loops: rows and columnsTranslate a shape into two loop roles and count the total work.Take a number apart, one digit at a timeUse remainder and division to process decimal digits, including zero.Multiple cases and a debugging mindsetCombine the patterns, isolate each case, and test the boundaries that can break your idea.Arrays: give every value a placeUnderstand indices, initialization, capacity, active length, and the first safe array loop.Scan, count, search, and compareDistinguish values from positions and preserve the exact tie rule a problem asks for.Change a sequence without losing itUpdate, copy, compare, reverse, and inspect neighbours using the correct bounds.Matrices: think in two coordinatesTraverse tables, total rows and columns, inspect diagonals, and protect grid neighbours.Characters become stringsSeparate characters from numbers, then safely inspect and edit managed text.Read the text the problem actually givesChoose words or full lines, preserve empty cases, and reset only the state that needs it.Scan text: count, filter, transformBuild a result from matching characters without losing leading zeros or skipping shifted text.Join, compare, and find textLearn content comparison, lexicographical order, substring counts, and the not-found sentinel.