Problems
The Power of the Hero#1893
Very easy · Brute force
Caravans#1894
Very easy · Prefix Sums · Brute force
Who visits early in the morning#1895
Easy · Graphs
Prince or Impostor#1896
Very easy · Strings · String suffix structures
Spinner Wheel#1897
Very easy · Probabilities
Tile Laying#1898
Very easy · Prefix Sums
Passage of the Corridor#1899
Easy · Implementation
Game#1900
Medium · Games · Math
A very friendly group#1902
Easy · Combinatorics · Bitmasks · Dynamic programming
Trees with an odd number of independent sets#1903
Medium · Dynamic programming
Maximum degree of a prime#1904
Hard · Number theory
Minimum degree of prime#1905
Medium · Number theory
Anniversary#1906
Hard · Math · Number theory
Trade#1907
Hard · Graphs · Greedy algorithms
Grid#1908
Easy · Geometry · Math
Drawing#1909
Medium · Dynamic programming · Probabilities · Combinatorics
Empire#1910
Very easy · Graphs
Reform#1911
Very hard · Graphs · Greedy algorithms
Constellation#1912
Easy · Graphs
Gifts#1913
Very hard · Graph matchings · Dynamic Programming Optimization
ICPC#1914
Very hard · Graphs
Numbers#1915
Very easy · Implementation
English#1916
Easy · Implementation
Diamond#1917
Easy · Dynamic programming
Puzzle#1918
Easy · Greedy algorithms · Sorting