_____for ik = ik - 1,n
______print ‘*’
How many stars will be printed for a given n and k.
# ([5], 'acm.sgu.ru':http://acm.sgu.ru/problem.php?contest=0&problem=222) Count the number of ways k rooks can be placed on a nxn chessboard so that they don’t attack each other.
# ([1], romanian county olympiad, 11th grade 2000, 'acm.sgu.ru':http://acm.sgu.ru/problem.php?contest=0&problem=356) Count the number of length n permutations with no fixed points. A fixed point in a permutation p is p(i) = i
# ([1], county level olympiad, 1994) Count the number of correct bracket sequences of length 2n.
# (10th grade math course) Count the number of paths on a grid going from 1,1 to n, m. At each step you can either increase your x coordinate or increase your y coordinate.
# ([5], 'acm.sgu.ru':http://acm.sgu.ru/problem.php?contest=0&problem=222) How many ways can k rooks be placed on a nxn chessboard so that they don’t attack each other.
# ([1], romanian county olympiad, 11th grade 2000, 'acm.sgu.ru':http://acm.sgu.ru/problem.php?contest=0&problem=356) How many permutations of length n have no fixed points. A fixed point in a permutation p is p(i) = i
# ([1], county level olympiad, 1994) How many correct bracket sequences of length 2n are there.
# (10th grade math course) How many paths are there on a grid from 1,1 to n, m if at each step you can either increase your x coordinate or increase your y coordinate.
# Given a permutation of numbers 1 to n, what's the minimum number of swaps one can use to get to the identity permutation.
# ([1], 'infoarena':problema/perm2) Given a permutation p what's the minimum k so that p^k(i) = i for all i in {1..n}.
# (romanian IOI selection 99, topcoder 2004, 'infoarena':problema/perm5) Find a permutation p of n elements which maximizes k so that p^k(i) = i for all i in {1..n}.
# ([1]) 6 people are at a party. Each two persons can be either friends or enemies. Prove that there is at least a group of three mutual friends or a group of three mutual enemies.
# (acm.sgu.ru) Count the number of circular black/white necklaces of length n. (babb is the same with bbab because the first necklace can be rotated to align with the second one)
# (acm.sgu.ru) How many length n black/white circular necklaces are there? (babb is the same with bbab because the first necklace can be rotated to align with the second one)
Some math books useful for programming competition entusiasts:
