duanxian0621的专栏

Problem Statement   XOR problems became very popular in TopCoder recently. (If you do not know the bitwise operation XOR, see the Notes section for an explanation.) That's why Elly decided to

Problem Statement   For a given string S of length n an inversion is a pair of integers (i, j) such that 0 S[j]. (That is, the character at 0-based index i is greater than the character at 0