Problems
Three digit numbers#4101
Medium · Brute force · Implementation
Email#4102
Very easy · Implementation
Roman Numerals#4103
Very easy · Implementation
Distance in Tree#4104
Very easy · Graphs
Sapper#4105
Very easy · Implementation
Subsets generation#4106
Very easy · Bitmasks · Implementation · Brute force
Totient Extreme#4107
Very easy · Number theory
RHTML Markup Language 1.0#4108
Easy · Implementation
Combining Rectangles#4109
Easy · Geometry
Route in the matrix#4110
Easy · Dynamic programming
Anagrams#4111
Very easy · Implementation
Military base#4112
Easy · Graphs · Depth-first Search
Heavy Cargo#4114
Very easy · Graphs · Shortest paths
Binary Search#4117
Hard · Binary Search
Frontier#4118
Easy · Geometry · Convex Hull
Disk Tree#4119
Easy · Implementation
Robot Navigation#4120
Medium · Breadth-first Search · Shortest paths · Graphs · Combinatorics
All Your Base#4121
Hard · Number theory · Constructive Algorithms
Periodic, My Dear Watson#4122
Easy · Brute force · Strings
This is Halloween: Saving Money#4123
Medium · Geometry · Math
Tile Art#4124
Very easy · Math
Thinking Inside the Box#4125
Hard · Geometry
Lightbulb Testing#4126
Hard · Expression parsing · Binary Search · Greedy algorithms
Operation: Merchant Boorinei#4127
Easy · Shortest paths · Graphs
Kingdoms#4128
Very easy · Graphs