MO Team Algorithm

Principle

1, offline operation.

2, divided into a number of blocks, the interval is sorted by block first, the block is sorted by the right boundary of the interval. The block size is generally sqrt (n).

3, according to the sequence of the operation of the interval, continuous interval transfer, update the answer.

Topics

1, small z socks (hose) HYSBZ-2038

Test instructions: There are n socks, the probability of finding two socks with the same color in the interval.

Idea: for interval [l,r], the probability is sum (cnt[i]* (cnt[i-1]) |i∈val[l,.., R])/[(r-l+1) * (R-L)]. Update the molecule according to Mo team's thought.

1#include <iostream>2#include <cstdio>3#include <algorithm>4#include <cmath>5 using namespacestd;6 Const intMAXN = 5e5 +Ten;7 Const intMAXM = 5e5 +Ten;8 intN, M;9 intUnit_len;Ten intBE[MAXN];//record the subscript L belongs to which sub-block One intVAL[MAXN]; A intCNT[MAXN]; - Long Longans; - Long LongANSA[MAXN],ANSB[MAXN];//answer A/b the structnode - { -     intL, R,id;//interval [l,r], input order -FriendBOOL operator< (ConstNODE&AMP;N1,Constnode&n2) +     { -         if(BE[N1.L] = = Be[n2.l])returnN1.R <N2.R; +         Else returnN1.L <N2.L; A     } at }QS[MAXM]; - Long LongGCD (Long LongALong Longb) - { -     if(A <b) Swap (A, b); -      while(b) -     { in         Long LongTMP = a%b; -A =b; tob =tmp; +     } -     returnA; the } * Long LongCalintx) $ {Panax Notoginseng     return1LL * x* (X-1); - } the voidUpdateintPosintv) + { AAns-=Cal (Cnt[val[pos]]); theCnt[val[pos]] + =v; +Ans + =Cal (Cnt[val[pos]]); - } $ voidSolve () $ { -     intL =1, r =0; -Ans =0; the      for(inti =1; I <= m; i++) -     {Wuyi         intID =qs[i].id; the          while(R < QS[I].R) Update (R +1,1), r++; -          while(R > QS[I].R) Update (R,-1), r--; Wu          while(L < QS[I].L) Update (L,-1), l++; -          while(L > QS[I].L) update (L-1,1), l--; About         if(ans = =0) Ansa[id] =0, Ansb[id] =1; $         Else -         { -Ansb[id]= Cal (QS[I].R-QS[I].L +1); -ansa[id]=ans; A             Long LongGCD =GCD (Ansa[id],ansb[id]); +Ansa[id]/=gcd; theAnsb[id]/=gcd; -         } $     } the } the intMain () the { the      while(~SCANF ("%d%d", &n, &m)) -     { inUnit_len =sqrt (n); the          for(inti =1; I <= N; i++) scanf ("%d", &val[i]); the          for(inti =1; I <= N; i++) Be[i] = I/unit_len +1; About          for(inti =1; I <= m; i++) scanf ("%d%d", &AMP;QS[I].L, &AMP;QS[I].R), qs[i].id=i; theSort (qs +1, QS +1+m); the solve (); the          for(inti =1; I <= m; i++) +         { -printf"%lld/%lld\n", Ansa[i], ansb[i]); the         }Bayi     } the  the  -     return 0; -}

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MO Team Algorithm