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Bipartite minimum vertex cover (alternative explanation)

Given an undirected bipartite graph find a minimum cardinality vertex set which covers all edges in the sense that it contains at least one endpoint of each edge.

sliding window

Given a string A (or array), and an integer k, find for every index i, the smallest index j (if it exists) such that {A[i],..,A[j-1]} consists of exact k distinct values.

maintaining the median of a dynamic set

Propose a data structure which permits to maintain a set of integers S, allowing to add elements and to remove the median. Both operations should work in logarithmic time.

Trapped rain over a landscape

Given a description of a landscape, describe how the rain water will drain.

Flooding a landscape

Given a description of a landscape, describe how it will be flooded by the water.

Encoding edges by weights

Given a graph, find weights for the vertices if possible, such that there is an edge between two vertices if and only if their total weight exceeds some threshold.

November Rain

You are given $n$ non intersecting line segments in the 2 dimensional plane. The segments are not parallel to the x-axis, nor to the y-axis and segments do not intersect. These segments represent roofs, and it is raining. Water flows down along the roofs, and pours from the lower endpoint to the roof below if there is one. The task is to compute how much water each roof receives.

Union of disjoint rectangles

Given $n$ rectilinear non overlapping rectangles, discovered the all connected components in their union.

How to practice algorithms with tryalgo

Hey, if you want to improve your skills in algorithmic problem solving, you don’t even need an online judge!

Constraint Programming

The framework

Searching a substring


Comment planifier une todo-list ?


Dessiner sans lever le crayon !


Alternating direction method of multipliers

Introducing ADMM!

Utiliser Paint pour les sudokus


Representing graphs in Python

How to represent a graph in Python ?

Trier un tableau en un nombre minimal d'étapes d'insertion

Le problème

Iterative Machine Teaching

This is a random discussion surrounding the ICML 2017 paper Iterative Machine Teaching.

Sieve of Eratosthenes

Compute for every integer n between 0 and N (excluded), the minimum number of operations to reduce it to zero. Allowed operations: decrease by 1 or divide by a factor, not larger than its square root.

Comment marche l'outil "Seau" de Paint ?