POJ 3368 区间数字出现最多次数

#include <stdio.h>
#include <iostream>
#include <queue>
#include <algorithm>
#include <map>
#include <vector>
#include <cmath>
#include <string.h>
#include <stdlib.h>
#include <time.h>
#include <fstream>
#include <set>
#include <stack>
#include <list>
using namespace std;

#define READ freopen("acm.in","r",stdin)
#define WRITE freopen("acm.out","w",stdout)
#define ll long long
#define ull unsigned long long
#define uint unsigned int
#define PII pair<int,int>
#define PDD pair<double,double>
#define fst first
#define sec second
#define MS(x,d) memset(x,d,sizeof(x))
#define INF 0x3f3f3f3f
#define ALL(x) x.begin(),x.end()
#define PB push_back
#define MOD 99991
#define MAX 111111

struct node
{
int l,fl;
int r,fr;
int m,fm;
}data[MAX<<2];
int num[MAX];
void PushUp(node &l,node &r,node &ans)
{
ans.l=l.l;
ans.fl=l.l==r.l?l.fl+r.fl:l.fl;
ans.r=r.r;
ans.fr=r.r==l.r?l.fr+r.fr:r.fr;
ans.m=l.fm>r.fm?l.m:r.m;
ans.fm=max(l.fm,r.fm);
if(l.r==r.l)
{
int tf=l.fr+r.fl;
if(tf>ans.fm)
ans.fm=tf,ans.m=l.r;
}
}
void build(int l,int r,int rt)
{
if(l==r)
{
data[rt]=(node){num[l],1,num[l],1,num[l],1};
return ;
}
int m=(l+r)>>1;
build(l,m,rt<<1);
build(m+1,r,rt<<1|1);
PushUp(data[rt<<1],data[rt<<1|1],data[rt]);
}

node query(int L,int R,int l,int r,int rt)
{
if(r<L||R<l)
{
node a;
return a;
}
//printf("L %d R %d l %d r %d\n",L,R,l,r);
if(L<=l&&r<=R)
return data[rt];
int m=(l+r)>>1;
node v1=query(L,R,l,m,rt<<1);
node v2=query(L,R,m+1,r,rt<<1|1);
if(m<L)
return v2;
if(R<=m)
return v1;
node v3;
PushUp(v1,v2,v3);
return v3;
}

int main()
{
//READ;
int n,q;
while(scanf("%d",&n)&&n)
{
if(!n)
return 0;
scanf("%d",&q);
for(int i=1;i<=n;i++)
scanf("%d",&num[i]);
build(1,n,1);
for(int i=1;i<=q;i++)
{
int l,r;
scanf("%d%d",&l,&r);
node ans=query(l,r,1,n,1);
//cout<<ans.m<<endl;
printf("%d\n",ans.fm);
}
}
return 0;
}