Problems
Guardian of Decency#433
Hard · Graphs
Romero’s Dilemma#434
Very easy · Graphs
Prime Path#435
Medium · Graphs · Breadth-first Search
Intersection#436
Hard · Geometry
Ancestors#437
Very easy · Disjoint set union
XML-converter#438
Hard · Implementation
Brackets#439
Easy · Dynamic programming · Math
Number Puzzle#440
Easy · Brute force · Strings
The most round number#441
Very easy · Implementation
Formations#442
Very easy · Number theory
ICQ#443
Very easy · Sorting
Battleships#444
Easy · Implementation
Excursion#445
Hard · Brute force · Math
Smooth Divisors#446
Easy · Math
Large number#447
Hard · Brute force · Implementation
Chords#448
Hard · Combinatorics
Equal Divisors 2#449
Hard · Math
Spiral#450
Easy · Brute force · Implementation
base64#451
Very hard · Implementation
Shelves#452
Medium · Sorting
Restaurants#453
Hard · Greedy algorithms · Implementation
Changeling#454
Very hard · Brute force · Implementation
Circular route#455
Very hard · Graphs
Game#456
Very hard · Probabilities
Close numbers#457
Medium · Data Structures · Binary Search