HDU - 1394 Minimum Inversion Number 求逆序数对 树状数组 (水题的理解)
Theinversionnumberofagivennumbersequencea1,a2,...,anisthenumberofpairs(ai,aj)thatsatisfyiaj.Foragivensequenceofnumbersa1,a2,...,an,ifwemovethefirstm>=0numberstotheendoftheseqence,wewillobtainanotherse