[Country Training team] Small Z socks (Mo team, probability)

Title Description

As a rambling person, little Z spends a lot of time every morning looking for a pair to wear from a bunch of colorful socks. Finally one day, little z can no longer endure this annoying to find socks process, so he decided to resign to fate ...

Specifically, small z to this n socks from 1 to n number, and then from the number L to R (L Although small z does not care about two socks is not a complete pair, even do not care about two socks whether a left and right, he is very concerned about the color of socks, after all, wearing two different color socks will be very embarrassing.

Your task is to tell Little Z how much he has the chance to draw two socks of the same color. Of course, Little Z wants this probability to be as high as possible, so he may ask multiple (l,r) to facilitate his choice.

However, in the case of l=r in the data, please judge this situation, output 0/1.

Input/output format

Input format:

The first line of the input file contains two positive integers n and M. n is the number of socks, M is the number of inquiries raised by small Z. The next line consists of n positive integer ci, where CI denotes the color of the sock, and the same color is represented by the same number. The next m line, two positive integer l for each line, R indicates a query.

Output format:

Contains m rows, for each query the output fraction of a line is a/b indicating the probability of randomly extracting two socks of the same color from the range [l,r] of the query. If the probability is 0 then output 0/1, otherwise the output of A/b must be the simplest fraction. (See examples)

Ideas:

Apparently a team of naked questions.

Two times the probability of taking a color is:

(A * (A-1))/((l-r+1) * (l-r) * *)

In that case, we'll spread him out.

The answer becomes(a^2+b^2+c^2+...x^2 − (R −l+1) Span class= "Mclose" >) / ( (r−l+1 ) ∗ (R −l) )

At this point, our purpose is to maintain intervals of squares of each color and

It's good to use Mo team.

Code:

#include <iostream>#include<cstdio>#include<algorithm>#include<cmath>#defineRii Register int i#defineRij Register Int J#defineint long Longusing namespacestd;structquery{intWZ,L,R,FZ,FM;} x[50005];intn,m,sy[50005],color[50005],len,ans,sum[50005];BOOLCMP (query Lk,query KL) {if(sy[lk.l]==SY[KL.L]) {        returnlk.r<KL.R; }    returnlk.l<KL.L;}voidChangeintWzintval) {ans-=sum[color[wz]]*Sum[color[wz]]; SUM[COLOR[WZ]]+=Val; Ans+=sum[color[wz]]*Sum[color[wz]];}BOOLcmp1 (Query Lk,query KL) {returnlk.wz<Kl.wz;}intgcdintVintW) {    if(v==0)    {        returnW; }    if(w%v==0)    {        returnv; }    returnGCD (w%v,v);} Signed Main () {scanf ("%lld%lld",&n,&m); Len=sqrt (n);  for(rii=1; i<=n;i++) {scanf ("%lld",&Color[i]); Sy[i]=i/len+1; }     for(rii=1; i<=m;i++) {scanf ("%lld%lld",&x[i].l,&X[I].R); X[i].wz=i; } sort (x+1, x+m+1, CMP); intL=1, r=0;  for(rii=1; i<=m;i++)    {         while(l<X[I].L) {Change (L,-1); L++; }         while(l>X[I].L) {Change (L-1,1); L--; }         while(r<X[I].R) {Change (R+1,1); R++; }         while(r>X[I].R) {Change (R,-1); R--; }        if(x[i].l==X[I].R) {X[I].FZ=0; X[i].fm=1; Continue; } x[i].fm= (r-l+1) * (rl); X[I].FZ=ans-(r-l+1); intgcd1=gcd (x[i].fz,x[i].fm); X[I].FZ/=GCD1; X[i].fm/=GCD1; } sort (x+1, x+m+1, CMP1);  for(rii=1; i<=m;i++) {printf ("%lld/%lld\n", x[i].fz,x[i].fm); }}

[Country Training team] Small Z socks (Mo team, probability)