Pergunta de entrevista da empresa Arcesium

Some puzzles. 1 DP question, 1question which can be solved with various type of solutions - Set,DP depending on constriants, 1 question related to strings. 1) Fastest Horse puzzle, Given 25 horses find fastes 1,2,3 horses in minimum races. 2) Give a barcode but defected one, represented by n*m array of 0,1 U have to find the minimum no, of changes to it so that each column has either 0 or either 1 and no k consecutive line contains same color. Each changeis to flip a bit. 3) Given numerical strings find the maximum no. that can be created by them.