import sys readline=sys.stdin.readline from collections import defaultdict def Inversion_Number(lst,weight=False,weakly=False): compress,decompress=Compress(lst) compressed_lst=[compress[x] for x in lst] N=len(compress) if not weight: weight=[1]*len(lst) ST=Segment_Tree(N,lambda x,y:x+y,0) inversion_number=0 for c,x in zip(weight,compressed_lst): inversion_number+=ST.Fold(x if weakly else x+1,N)*c ST[x]+=c return inversion_number def Compress(lst): decomp=sorted(list(set(lst))) comp={x:i for i,x in enumerate(decomp)} return comp,decomp class Segment_Tree: def __init__(self,N,f,e,lst=None,dynamic=False): self.f=f self.e=e self.N=N if dynamic: self.segment_tree=defaultdict(lambda:self.e) else: if lst==None: self.segment_tree=[self.e]*2*self.N else: assert len(lst)<=self.N self.segment_tree=[self.e]*self.N+[x for x in lst]+[self.e]*(N-len(lst)) for i in range(self.N-1,0,-1): self.segment_tree[i]=self.f(self.segment_tree[i<<1],self.segment_tree[i<<1|1]) def __getitem__(self,i): if type(i)==int: if -self.N<=i<0: return self.segment_tree[i+self.N*2] elif 0<=i1: i>>= 1 self.segment_tree[i]=self.f(self.segment_tree[i<<1],self.segment_tree[i<<1|1]) def Build(self,lst): for i,x in enumerate(lst,self.N): self.segment_tree[i]=x for i in range(self.N-1,0,-1): self.segment_tree[i]=self.f(self.segment_tree[i<<1],self.segment_tree[i<<1|1]) def Fold(self,L=None,R=None): if L==None: L=self.N else: L+=self.N if R==None: R=self.N*2 else: R+=self.N vL=self.e vR=self.e while L>=1 R>>=1 return self.f(vL,vR) def Fold_Index(self,L=None,R=None): if L==None: L=self.N else: L+=self.N if R==None: R=self.N*2 else: R+=self.N if L==R: return None x=self.Fold(L-self.N,R-self.N) while L>=1 R>>=1 while i>=1 r>>=1 if f(self.f(vl,vr)): return self.N v=self.e while True: while L%2==0: L>>=1 vv=self.f(v,self.segment_tree[L]) if f(vv): v=vv L+=1 else: while L>=1 r>>=1 if f(self.f(vl,vr)): return 0 v=self.e while True: R-=1 while R>1 and R%2: R>>=1 vv=self.f(self.segment_tree[R],v) if f(vv): v=vv else: while R